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“Meet the Flockers” – Myths of Monogamy

Southern Rockhopper Penguin pair

“Meet the Flockers” – Myths of Monogamy

By Martin Franklin

Monogamy

Monogamy can mean different things to different people, encompassing, for example:

  • Marital monogamy, i.e. marriages of only two people (in contrast to polygamy).
  • Social monogamy, i.e. two partners living together/sharing a territory and cooperating in securing basic resources (e.g. food and shelter).
  • Sexual monogamy, i.e. two partners having an exclusive sexual relationship.
  • Genetic monogamy i.e. sexual monogamy with DNA evidence of the two partners reproducing exclusively with each other. 

Monogamy within human societies

It has been suggested that few human societies are monogamous, despite what many of us like to believe. For example, of 1,231 societies reviewed in one study:

  • 186 were deemed monogamous; 
  • 453 displayed occasional polygyny (where a man has multiple wives simultaneously); 
  • 588 displayed frequent polygyny; and 
  • 4 displayed polyandry (where a woman has multiple husbands simultaneously).1

Monogamy within mammalian societies

It is reckoned that only around 3–5% of all mammal species are socially monogamous2,3, though around 29% of primate species are considered socially monogamous.4

One fairly accurate predictor as to whether males within a primate species are likely to be monogamous or have several sexual partners at one time is to look at their testicle size5,6. I would suggest, however, that for reasons of both safety and odour, one should not look too closely. 

The rule of thumb is that the smaller the testicles (relative to overall body size), the more likely that species is to be monogamous. Accordingly, for example, highly promiscuous male chimpanzees have relatively large testes (thus producing more sperm, with a corresponding impregnation advantage), whereas male gorillas have relatively small testes (as gorilla society has a polygynous mating system in which the dominant male avoids sperm competition by controlling access to females).

Monogamy within other taxa

In relation to non-mammalians, it is frequently suggested that while, for example, there are relatively few known examples of reptiles, amphibians, fish and invertebrates being socially monogamous (one fascinating example being a common parasitic fluke that lives in human blood7, around 90% of birds are socially monogamous.8

Monogamy within avian societies 

By “monogamy within avian societies” I refer, of course, to the behaviour of birds of the same species, not people who belong to bird societies, not least as I assume that members of this latter group are typically lucky to engage in recreational copulation at all, let alone have the opportunity to acquire more than one sexual partner. (I may, or may not, belong myself to one or more such bird societies.)

But back to the point. “Monogamy” in birds may be considered “a prolonged pair bond with a single member of the opposite sex for purposes of raising young”.9 Unlike most reptiles and amphibians, that typically leave their eggs once laid, bird eggs (and subsequently chicks) typically need significant care from both parents (e.g. nest building, defense of the territory, incubation, and fetching food for the parent tending the egg(s)/chick(s) and/or the chick(s) themselves). Accordingly, it seems that most birds are indeed monogamous (at least socially).9

Exceptions within avian societies

It shouldn’t be assumed however, that such pair bonds will be “till death do us part”. 

While some birds (e.g. many parrots and eagles) do indeed form life-long pairs, others will only do so if their partner from the previous mating season arrives (post winter migration) within the same week (or so) at the nesting site (e.g. black-tailed gotwits). 

Others (e.g. female oystercatchers and female blue tits) will readily leave their partners if more attractive territories become offered by other suitors. 

Even within socially monogamous pairs, it’s now believed that birds are only very rarely sexually monogamous. 

One significant study found that in approximately 90% of the species studied there were “extra-pair offspring” (i.e. offspring fathered by a male other than the social father), and on average over 11% of offspring were not fathered by the social father.10 

Such behaviour may be an insurance against a mate’s potential infertility and/or way of ensuring genetic variability and/or robust immune systems in the offspring and/or (where the extra-pair copulation is with a male superior to the social father) offspring of improved quality and diversity.9 

Plus, of course, a significant minority of birds are polygynous (probably fewer than 10%). Broadly speaking, when the following occurs:

  • the more impressive the male’s song and more beautiful the male’s plumage (relative to the female); together with either
  • the ability of a male to control scarce resources (e.g. golden-backed weavers); or
  • there being no need for males to find food for their offspring (e.g. where there’s an abundance of fruit for frugivore species, as is the case for most birds-of-paradise)…
Southern Rockhopper Penguin pair
Southern Rockhopper Penguin pair (Source: Penguins International photo library)

…then the more likely it is to be a species where the male copulates with numerous females (or, as Iago might have put it to Brabantio, makes “the beast with two beaks”).9

Monogamy within penguin societies

What, then, of penguins? Given that in all penguin species, both the male and female play an essential extensive and complementary role in incubation and chick-rearing, and given that no individual can control available resources, we would expect widespread monogamy. 

Available evidence confirms this to be the case: all penguin species are believed to display widespread sexually monogamous behaviour each breeding season.11

Seasonal monogamy within penguin societies

That said, many individuals will choose a different mate from season to season. 

Across all penguin species, it is believed that, on average, around 60-90% of pairs remain together over successive seasons, though this drops as low as 15% in Emperor Penguins. 

One of the factors which seems to drive a pair to separate is the failure to find a partner that complements the often complicated nest-relief patterns of penguins (i.e. taking turns to incubate the egg/protect the chick(s) and hunt for food for the chick(s), in each case returning before the partner/chick(s) starve). Accordingly:

  • In species that take long turns on the nest (e.g. Adelie and Macaroni Penguins), if a pair fails to synchronise effectively and raise a chick in any given year, they are less likely to pair up again the next year. 
  • Conversely, there seems to be no such correlation in species that take frequent short turns on the nest (e.g. Gentoo Penguins).11
Humboldt Penguins copulating (© Martin Franklin/ZSL)

Penguin “cheaters”

Individual penguins are also known to “cheat” on their partners. For example, female Adelie Penguins may mate with a new male if their partner from the previous year is late returning to the nest site (following which such females have been observed returning to their former partner upon his arrival, and this cuckolded male then incubating the egg(s) fertilised by the first male). 

Similarly, my colleagues at ZSL London Zoo have observed a few individual female Humboldt Penguins regularly and openly mating with more than one male in the same season, with one particular individual regularly flitting between two adjacent nest-boxes, each occupied by males with whom she copulates.

So why stay together in the long-term?

Ultimately there seems (unlike in some birds, including skuas) to be no increased breeding success rate for penguin pairs that remain together for several seasons. Researchers have suggested, therefore, that many penguin pairs simply stay together because they have had offspring, and finding (or having to compete for) a new mate would be potentially too much trouble.11 And who says we anthropomorphise penguins too much?

© Martin Franklin 2019

Martin Franklin is a bird keeper at ZSL London Zoo, and works extensively with Humboldt Penguins. Any views or opinions expressed in this article are the author’s own, and do not necessarily represent those of ZSL.

Penguins, monogamy, or cheaters…? Amazing what we have learned. Let us know what you think.  And please help us to continue to provide you with penguin news articles by donating to Penguins International.

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References

1 Ethnographic Atlas, a database coded by George P. Murdock and published in 29 successive installments in the journal Ethnology, 1962-1980.

2 Kleiman, D. G. (1977). Monogamy in Mammals. The Quarterly Review of Biology. 52 (1): 39–69.

3 Lukas, D. and Clutton-Brock, T. (2012). Cooperative breeding and monogamy in mammalian societies. Proceedings of the Royal Society B: Biological Sciences. 279 (1736): 2151–6.

4 Lukas, D. Clutton-Brock, T. (2013). The Evolution of Social Monogamy in Mammals. Science. 341 (6145): 526–530.

5 Dixson, A. and Anderson, M. (2001). Sexual selection and the comparative anatomy of reproduction in monkeys, apes, and human beings. Annual Review of Sex Research. 12: 121–144. 

6 Harcourt, A. H., Harvey, P. H., Larson, S.G. and Short, R. V. (1981). Testis weight, body weight and breeding system in primates. Nature. 293 (5827): 55–57. 

7 Beltran, S. and Boissier, J. (2008). Schistosome monogamy: who, how, and why? Trends in Parasitology 24 (9): 386–91.

8 Lack, D. (1968). Ecological adaptations for breeding in birds. Science. 163: 1185–1187.

9 Gill, F. B. and Prum, R. O. (2019). Ornithology. (4th edition). W. H. Freeman and Company: New York.

10 Griffith, S. C., Owens, I. P. F. and Thuman, K. A. (2008). Extra pair paternity in birds: a review of interspecific variation and adaptive function. Molecular Ecology. 11: 2195-2212.

11 Williams, T. D. (1995). The Penguins. Oxford University Press: New York.

How Can You Help Penguins?

Gentoo Penguins and sheep

How Can You Help Penguins?

By Beth Storey-Jones

Threats to penguins

There are many threats to penguins. From toxic plastics, resource competition, habitat destruction to invasive species, these animals need as much help as we can possibly give them. First, we will look into the problem’s penguins are facing on a regular basis and what can be done to help now and in the future.

Plastic pollution

In a 2015 study, Wilcox and his colleagues predicted that the concentration of plastics found in the ocean globally would be up to 580,000 pieces per km2 affecting around 186 different seabird species including penguins[1]. The two main ways that plastic effects wildlife is through ingestion and entanglement. Ingestion ranges in its effects, causing blockages in the gut and the leaching of toxins that eventually damage vital organs, which can lead to cancers and offspring birth defects[2]. Entanglement is just as fatal, with many species unable to free themselves from non – perishable plastics and discarded fishing equipment. Leading us onto the next threat to penguins: overfishing.

Image  1 : An African Penguin struggling to free his/her bill from a piece of plastic debris. This will inhibit his/her ability to eat, appropriately swim and even effectively breathe. (Source: Avery, 2018).

Competition for resources 

Penguin diets consists almost exclusively of fish. According Trathan, et al (2014), there is currently a shortage of studies that investigate the relationship and interactions that occur between commercial fishing and the effect on local penguin populations [3]. One of these such studies by Crawford, et al (2011) looked into the collapse of populations of penguins in South Africa. They found strong evidence to suggest that both the fishing industry and environmental instability played a part, with the penguins substituting sardines for nutrient lacking pelagic gobies [4]. Anchovies were also a staple for penguins in the past, but they also fell victim to overfishing when the sardines disappeared from the area during the 1060’s [5]. 

Encroachment and habitat degradation 

Chile is home to 80% of the world’s Humboldt Penguin population. An interesting Oceana- commissioned study found that nesting sites were being threatened by the creation of 2 open pit mines. To protect the species, Oceana Chile partnered with other NPOs (non-profit organisations) and the concerned Chilean community to oppose the development that would increase pollution and oil spills as well as create noise pollution, habitat loss and encroachment [6]. 

A lesser known issue for penguins is habitat degradation, caused by invasive or domestic species. An example of this can be seen in the Falkland Islands, where livestock is damaging vegetation cover for penguin chicks, which can be fatal during rainfall [7]. Large populations of grazing rabbits also have had this same effect on Macquarie Island, but more substantially their over-consumption of the land has led to major landslides decimating breeding grounds. The invasive species crisis isn’t a modern problem. It can be seen dating right back to the 1600’s when whalers and other sea dwelling humans introduced species such as black rats to the Galapagos Islands. A couple of hundred years later when the island’s human population increased, domestic animals such as dogs and pigs where also introduced, as well as cats. Records state that one cat that inhabited Isabela Island increased adult penguin mortality by 49% each year! [8]

Image 2: Penguins often have to share their habitat with farmland. (Source: Penguins International photo library)

The Climate Crisis 

How climate change directly effects penguins is still being researched. However, studies into how their environment is affected both in the short term and in the long term is extensive. 

Increased snowfall as a result of warmer conditions is contributing to Adelie chick mortality in Antarctica [9]. Similarly, an increase in storm frequency in Argentina has resulted in increased reproductive failure in Magellanic Penguins [10]. Southern Rockhopper Penguins are declining due to the decrease in condition of parent penguins, due to lacking food resources, resulting in low survival success of hatchlings [11]. 

Image 3: Sadly, Adelie chicks are starving while parents struggle to find food. (Source: Griffin, 2017).

So, what can you do to help…?

It’s pretty tricky to know how you can directly help penguins, especially when they live in remote parts of the world. But there are lots of ways you can help to create a healthy environment for them to live in. And you can do this without spending a penny (even saving a bit in some cases!) These include: 

  • Ensure any fish you purchase is from sustainable, well managed fisheries 
  • Cut back on products packaged in plastic or plastic-based items
  • Make sure you are recycling whenever you can and disposing of other waste correctly. 

To help with the climate change crisis, you can: 

  • Reduce the meat you eat 
  • Buy less, especially if it is unnecessary 
  • Using public transport where possible 
  • Arguably one of the most important points, use your voice! Support your politicians and community in their battles to strengthen climate change science. 

You can also help in other ways, such as supporting Penguins International directly by:

  • Donating to one of the “Help Penguins Now” causes. 
  • Create a free “Facebook Birthday Fundraiser”
  • Adopt-a-Penguin (a perfect gift for a penguin loving friend or family member!) 
  • Donate to the “Penguin Clean Up Fund”
  • Become a sponsor

What did you learn about all the threats to penguins and the simple things we can do to help? Let us know.  And please help us to continue to provide you with penguin news articles by donating to Penguins International.

Read more about penguins in some of our other blogs:

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Reference List

  1. Wilcox, C., Sebille, E., and Hardesty, B. (2015). Threat of plastic to seabirds is global, pervasive, and increasing. Proceedings of the National Academy of Sciences of the United States. 112 11899-11904 
  2. Derraik, J. (2002). The Pollution of the Marine Environment by Plastic Debris: A Review. Marine Pollutant Bulletin. 44, 842-852. 
  3. Trathan, P., Garcia-Borboroglu, P., Boersma, D., Bost, C-A., Robert, J., Crawford, R., Crossin, G., Cuthbert, R., Dann, P., Davis, L., De La Puente, S., Ellenberg, U., Lynch, H., Mattern, T., Putz, K., Seddon, P., Trivelpiece, W., and Wienecke, B. (2014). Population, habitat loss, fishing and climate change as critical threats to penguins. Conservation Biology. 29, 31-41
  4. Crawford, R., Altwegg, R., Barham, B., Barham, P., Durant, J., Dyer, B., Geldenhuys, D., Makhado, A., Pichegru, L., Ryan, P., Underhill, L., Upfold, L., Visagie, J., Waller, L., and Whittington, P. (2011). Collapse of South Africa’s Penguins in the early 21st Century. African Journal of Marine Science. 33, 139-156. 
  5. Ludynia, K., J.‐P. Roux, R. Jones, J. Kemper, and L. G. Underhill. (2010). Surviving off junk: low‐energy prey dominates the diet of African penguins Spheniscus demersus at Mercury Island, Namibia, between 1996 and 2009. African Journal of Marine Science 32:563–572.
  6. Oceana, 2017. Oceana reports severe flaws in the environmental proceedings of Dominga and requests rejecting the project. [online]. Oceana. Available from: https://oceana.org/press-center/press-releases/oceana-reports-severe-flaws-environmental-proceedings-dominga-and [Accessed 10 December 2019]
  7. Demongin, L., Poisbleau, I., Strange, J., and Quillfeldt, P. (2010). Effects of severe rains on the mortality of southern rockhopper penguin (Eudyptes chrysocome) chicks and its impact on breeding success. Ornitologia Neotropical. 21,430–443.
  8. Tasmania Parks and Wildlife Services. (2013). Macquarie Island pest eradication project. [online]. Tasmanian Government. Available from: https://parks.tas.gov.au/Documents/Evaluation_Report_Macquarie_Island_Pest_Eradication_Project.pdf [Accessed 10 December 2019].
  9. Ducklow, H., Baker, K., Martinson, D., Quentin, L., Ross, R., Smith, R., Stammerjohn. S., Vernet, M., Fraser, M. (2007). Marine pelagic ecosystems: The West Antarctic Peninsula. Philosophical Transactions Royal Society Series B. 362, 67–94.
  10. Boersma, P., and Rebstock, G. (2010). Effects of double bands on Magellanic penguins. Journal of Field Ornithology. 81, 195–205.
  11. Crawford, R., Makhado, A., Upfold, L., and Dyer, B. (2008). Mass on arrival of rockhopper penguins at Marion Island correlated with breeding success. African Journal of Marine Science. 30, 185–188.

 

Images 

 

  1. Avery, M. (2018). Guy Shorrock – Plastic Perils and Penguins. [online]. WordPress. Available from: https://markavery.info/2018/01/28/guy-shorrock-plastics-perils-penguins/ [Accessed 10 December 2019].
  2. Farmers Weekly. (2018). Farming on the front line: Sheep in the Falkland Islands. [online] Farmers Weekly. Available from: https://www.fwi.co.uk/international-agriculture/farming-front-line-sheep-falkland-islands [Accessed 10 December 2019].

3. Griffin, A, 2017. Thousands of tiny baby Adelie Penguin starve to death as changing weather forces parents to travel for food. [online]. Independent. Available from: https://www.independent.co.uk/environment/baby-penguins-adelie-global-warming-climate-change-wwf-chicks-dead-parents-a7997396.html [Accessed 10 December 2019].

How Do Penguins Swim So Well?

King Penguins swimming in the ocean

How Do Penguins Swim So Well?

By Sian Liversage

Emperor Penguin using its fast swimming speed to propel out of the water. Image © National Geographic by Paul Nicklen.

The unusual aquatic lifestyle of penguins has determined their shape, colouration, what they eat, where they go on land, how they breed and overall their geographic range and distribution.

Chinstrap Penguin swimming in the ocean (Source: Penguins International photo library)

Body Adaptations for Penguin Swimming Speed

Just by looking at a penguin, it is clear to see that their bodies have been specially adapted for swimming. They have developed a streamlined body shape that reduces drag when they are in the water; a shape which has also been adopted by fish and marine mammals. Their wings (called “flippers” on penguins) and feet also serve a purpose. Although their flippers are not much use on land, they function like propellers when underwater, allowing them to move forward and increase their speed dramatically. Whilst swimming, their webbed feet get tucked away near the tail to be used to navigate through the water. 

All penguin bodies are covered in oily feathers, which create a water-tight layer and allows the water to flow smoothly over their bodies, thus reducing drag. But this is not the only thing a penguin’s body can do.

There’s a secret to how penguins can swim so fast through the water

Back in 2012, marine biologists discovered the mystery behind how Emperor Penguins rocket through the water. The conclusion of this was down to the stream of bubbles left in the penguin’s wake. Thanks to their miniscule feather filaments, penguins can trap air under their feathers. It was discovered that when Emperor Penguins fluff these tiny feathers underwater, they release bubbles that will then reduce the density of the water surrounding them. These bubbles act like a lubricant to reduce drag, just like an Olympic swimmer’s swimsuit. With this extra boost, these penguins can double or triple the speeds at which they usually travel, so this adaptation can help to propel individuals onto land or help with avoiding a predator. 

In addition to help from bubbles, a penguin’s blood will help them to stay underwater for longer. The blood is primarily made up of haemoglobin, which helps to carry extra oxygen around the body, and myoglobin is found in their muscle tissue, allowing oxygen to be stored, therefore helping them to breathe underwater for enough time to hunt.

Penguin Swimming Techniques

Not only have these birds evolved and adapted perfectly to being in the water, but they have also developed incredibly successful swimming techniques too. Most species of penguin will swim together, in a small or a large group, when looking for food. Sometimes penguins may swim below the surface and dive for a couple minutes and then resurface. For long journeys, however, many penguins use a technique known as “porpoising”; a very similar technique used in marine mammals. This is when a penguin will propel forward out of the water, allowing them to catch a breath as they do so. When penguins do this, they can increase their speed by a substantial amount (See video above).

Some colonies have a danger zone around the surrounding edges of their site, where predators are often waiting for an opportunity to catch a meal. Those penguins that have these danger zones, will often porpoise as soon as they enter the water to give themselves a good chance to escape any danger. Therefore, this technique is ideal for predator avoidance but can also be used for travelling long distance to find food.

Royal penguin. Adult porpoising. Macquarie Island, December 2015. Image © Edin Whitehead by Edin Whitehead www.edinz.com

Conclusion

Despite penguins being birds that have lost the ability to fly, who come across somewhat clumsy on land, they have shown to be one of the most successful aquatic birds based on their adaptations and techniques when swimming. The more research is conducted, the more we are astonished at their capabilities. They are certainly a species that should not be underestimated!

Did you know about the amazing way penguins swim and how they adapt? Let us know what you learned.  And please help us to continue to provide you with penguin news articles by donating to Penguins International.

Read more about penguins in some of our other blogs:

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References:

  1. Davis, L. Renner, M. 2003. Penguins. T & AD Poysner, London. 
  2. New York Daily News. 2012. Scientists solve mystery of penguins’ incredibly fast underwater swimming speed: a secret layer of bubbles. Webpage: https://www.nydailynews.com/news/world/mystery-penguin-fast-swimming-discovered-article-1.1188268
  3. Penguins Blog. How fast can penguins swim? Webpage: https://penguinsblog.com/how-fast-can-penguins-swim/

Sciencing. 2017. How do Penguins Swim? Webpage: https://sciencing.com/penguins-swim-4567568.html

Spheniscidae Superlatives – Penguin Best of the Best

Emperor Penguin with Mount Erebus

Spheniscidae Superlatives – Penguin Best of the Best

By Megan Spofford

Do you remember the section of the high school yearbook that displayed classmate’s photographs and the various superlatives they had been voted for? Well, take a look at Penguin International High’s 2019 Yearbook and see which superlative each species has been awarded!

Rarest Penguin

Yellow-eyed Penguin – You won’t find many of these birds around, because they are unfortunately the most endangered of the penguin species. The IUCN Red List classifies the Yellow-eyed Penguin as endangered with only 2500-3500 adult individuals of the species, and they inhabit only a small range of land. Additionally, population status shows a decreasing trend. This assessment was last completed in August 2018

A rare Yellow-eyed Penguin
(Source: Penguins International photo library)

Best Make-up

Royal Penguins get best make-up, because they are the only species of penguin with white “cheeks.” It almost looks as though they have applied powder!

Photo credit: ARKive

Coolest Penguin

Adelie Penguins (along with Emperor Penguins) spend their entire lives on the Antarctic continent. The most southerly colony of penguins is made up of Adelies.

Bullies

It’s a shame that this penguin is the most common in the wild, because they are also the meanest! Macaroni Penguins are known for being terribly territorial and aggressive, which is what qualified them for this superlative.

 

Fastest Swimmers

Unconfirmed reports clock Gentoos in at a whopping 22 mph (or 35 kph) in the water, making them the fastest swimmers out of all of the penguin species. 

 

Best Divers

Emperor Penguins have the record for longest dive time of all penguins, but they also hold the record for the deepest dive of all birds. Tracking devices that record diving depths and times were attached to Emperor Penguins while they hunted, and data showed that the average diving depth was between 100-200 m. However, the deepest dive for an Emperor Penguin was recorded at 565 m. Furthermore, the longest record for Emperor Penguin breath-holding was at 22 min. (It’s important to note that this record is on the extreme end of the spectrum, with average Emperor Penguin dive times being much lower around 3-6 minutes.)

 

Marathon Swimmers

Fiordland Penguins are another species that had tracking devices attached to individuals, and the data those devices revealed was that in a period of 8-10 weeks, Fiordland Penguins had traveled 7000 km roundtrip to hunt for food! This incredibly long journey allowed Fiordland Penguins to hunt as much as possible so they could bulk up, and be ready for molting. Some scientists question whether this has always been a natural route for Fiordland Penguins, or if limited food resources have caused the bird to adapt to more extreme migratory patterns.

Best Beard

Chinstrap Penguins are easily recognizable by the black band that swoops under their necks from each side of the head. No other penguins have this distinctive marking. Do we call it a beard, or a goatee?

Photo credit: ARKive

Gravity-Defying Eyebrows

While there are 7 different penguins that have crest features, the Erect-crested Penguin has one that sticks straight up over its head! The other crested species have longer crests that droop down to the sides.

Best Vocal Group

These birds that belong to the genus Spheniscus, are sometimes called the Banded Penguins not because they are in a rock group together, but because of the distinctive band they have  running across their chests. These 4 species also have the loudest vocalizations, which sound like a donkey braying. The quartet includes the African, Humboldt, Magellanic, and Galapagos Penguins.

The Late Bloomer

The breeding cycle for the King Penguin is longer than that of the other species, with it taking 13-16 months for a full cycle to occur. Because this cycle is longer than one year, there are always chicks of various ages in a King Penguin colony.

Night Owl

Well, I guess technically this one would be a Night Penguin. The Little Penguin is the only species that is truly nocturnal!  

Plain Jane

There is always one of these in the group, and it’s not a bad thing! The Snares Penguin blends in with the rest of the crowd of crested penguins and penguins that are endemic to New Zealand.

Prettiest Eyes

Both Southern and Northern Rockhoppers take this award as they uniquely have red-colored eyes that stand out against the black feathers surrounding them.

Southern Rockhopper Penguin — Doesn’t it have beautiful eyes??
(Source: Penguins International photo library)

With such a unique array of characteristics, it’s no wonder that people easily fall in love with this charismatic animal. Thanks for taking a look at our penguin superlatives!

Wow, who knew about all these penguin awards! Let us know if you think there should be more or a different penguin species should win one of these categories. And please help us to continue to provide you with penguin news articles by donating to Penguins International.

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References

 

  1. About Little Penguins, Penguin Foundation Phillip Island, https://penguinfoundation.org.au/about-little-penguins/.
  2. “Banded Penguins (Genus Spheniscus).” INaturalist.org, https://www.inaturalist.org/taxa/3811-Spheniscus.
  3. BirdLife International 2018. Megadyptes antipodes. The IUCN Red List of Threatened Species 2018: e.T22697800A132603494.                                                                                                                                    http://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T22697800A132603494.en. [Downloaded on 01 September 2019.]
  4. “Emperor Penguins Diving and Travelling.” Australian Antarctic Division: Leading Australia’s Antarctic Program, Australian Government, Department of the Environment and Energy, Australian Antarctic Division, 24 Sept. 2014, http://www.antarctica.gov.au/about-antarctica/wildlife/animals/penguins/emperor-penguins/how-deep-can-they-dive.
  5. Evans, Tessa. “Fiordland Penguins Swim up to 80km a Day.” Scimex, Scimex, 29 Aug. 2018, https://www.scimex.org/newsfeed/fiordland-penguins-swim-up-to-80km-a-day.
  6. “Gentoo Penguin.” National Geographic, National Geographic, 24 Sept. 2018, https://www.nationalgeographic.com/animals/birds/g/gentoo-penguin/.

“King Penguins.” Australian Antarctic Division: Leading Australia’s Antarctic Program, Australian Government, Department of the Environment and Energy, Australian Antarctic Division, 20 Mar. 2018, http://www.antarctica.gov.au/about-antarctica/wildlife/animals/penguins/king-penguins.

The Usefulness of Penguin Poo

penguin poo, what is special about penguin poo, why is penguin poo valuable, scientific investigation of penguin poo, why is there so much penguin poo on the snow

The Usefulness of Penguin Poo

by Jodie King

Let’s talk about poo. All animals produce it but there’s something rather special about penguin poo. Guano is excrement produced specifically from bats and seabirds (poop), including the 18 species of penguin that waddle around the Southern Hemisphere of our planet.

What’s so special about penguin poop?

Many species of penguin including Humboldt Penguins use guano to build their nests. They scrape out layers of soil and poo using the claws on their feet to create burrows. These burrows offer protection for themselves and their chicks from the elements and any potential predators. However, not only is penguin poo a brilliant resource for penguins, it has been highly sought after for use by humans. 

Guano is normally used as a fertiliser as it is very high in nitrogen but has even been used to manufacture gunpowder! It was highly sought after during the early 19th century before the use of synthetic fertilizers, and was primarily extracted from Peru, the home of the Humboldt Penguin.

While using penguin poo is highly resourceful, the collection of guano can be devastating for penguins, as it destroys potential sites for nesting. Parent penguins are forced to create small scrapes on the surface of the substrate which provide little to no protection for their vulnerable chick.

There’s a lot of penguin guano in a penguin colony. Let’s face it, penguins poop a lot!
(Source: Penguins International photo library)
Want to see just how much penguins actually poop? Check out this video. But we’ll warn you, there’s a lot of penguin pooping going on here! Not for the faint of heart.

What’s being done to fix this problem of penguin guano harvesting?

Despite this, it’s not all doom and gloom. Researchers have been investigating whether areas which have been overharvested for guano can be provided with manmade nest boxes. They have even gone to great lengths to investigate which types of material can mimic a natural African Penguin burrow the best, providing the appropriate levels of warmth and humidity. Additionally, to tackle the problem directly, sustainable guano harvesting has been introduced and walls have been erected around the nesting seabirds to protect them from the guano trade2.  In some areas the penguins even have their own guards.

BUT this isn’t all penguin poo is useful for!

Penguin poo is also valuable for science and penguin conservation

Analysing guano can tell us vital information about penguins and their conservation. 

What you probably didn’t know is that we have been monitoring penguins from space for over 30 years. In 1984, a NASA scientist called Mathew Schwaller suggested that satellites could be used to investigate penguin colonies3. Initially, scientists focused on surveying the Adélie Penguin, a species which only resides in Antarctica. This species has a diet which is mostly made up of krill (which makes their guano bright pink!), but might also make them vulnerable due to human fishing activities. Simplifying a highly complex method, the penguin guano and nesting materials can be distinguished from surrounding substrate using satellites. Using this comparison technique, new penguin colonies can be discovered on remote islands which have little or no access for people and would otherwise not have been found. And we can even look at estimating the number of penguins in the colony to track the abundance pattern4. The wonderful thing is, as technology improves, the image resolution increases and the ability to obtain information is far easier and much more superior.

Many penguins use guano to help build their nests or burrows.
(Source: Penguins International photo library)

Scientists are actually investigating penguin poo quality!

Investigating poo quantity (from space!) not only tells us about the number of penguins currently in the colony, but can also give a glimpse into the abundance of penguins throughout history. These colony estimates can then be compared to information such as food availability or environmental changes in the same years to establish whether there are any trends in colony declines or increases. On the other hand, it can be used to help provide this information and indicate the condition of the marine ecosystem as the penguins rely on an abundance of fish and small crustaceans to survive. 

A wonderful example of this in action can be seen by researchers Roberts et al. (2017). Using the 84.5g of guano that a Gentoo Penguin produces each day, they investigated the impact of volcanic eruptions on the penguin colony size from an impressive 8,500 years ago!5

Put simply, penguin poop is wonderful stuff. It not only provides penguins with a nest to shelter from the elements and to raise chicks, but offers humans with a highly effective way to fertilise crops. Even more than that, it provides a wealth of information about many penguin species and can even act as an indicator for the diversity of wildlife around them.

Penguin guano actually provides valuable information to researchers.
(Source: Penguins International photo library)

Did you know how useful penguin poo can be? Please let us know what you learned. And please help us to continue to provide you with penguin news articles by donating to Penguins International.

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Useful references:

1. Bonnie R., Lei & Green, Jonathan & Pichegru, Lorien. (2013). Extreme microclimate conditions in artificial nests for Endangered African Penguins. Bird Conservation International. 24. 10.1017/S0959270913000671.

2. https://www.iucn.org/content/bird-droppings-biodiversity-paradise-%E2%80%93-guano-islands-and-capes-national-reserve-system-peru

3. Schwaller, M. R., Olson Jr, C. E., Ma, Z., Zhu, Z., & Dahmer, P. (1989). A remote sensing analysis of Adélie penguin rookeries. Remote sensing of environment, 28, 199-206.

4. Lynch, H. J., & Schwaller, M. R. (2014). Mapping the abundance and distribution of Adélie penguins using Landsat-7: first steps towards an integrated multi-sensor pipeline for tracking populations at the continental scale. PloS one, 9(11), e113301. doi:10.1371/journal.pone.0113301

5. Roberts, S. J., Monien, P., Foster, L. C., Loftfield, J., Hocking, E. P., Schnetger, B., … & Ochyra, R. (2017). Past penguin colony responses to explosive volcanism on the Antarctic Peninsula. Nature communications8, 14914.

Wildlife Tourism – Is it affecting penguins?

Tourist with Chinstrap Penguin

Wildlife Tourism – Is it affecting penguins?

by Georgia Podmore

Where can I go to see penguins on vacation? This is a common search phrase on internet search engines. There are a variety of countries around the world that have wild penguins and it may seem that no harm is caused from tourists travelling out to experience wild penguins in their natural habitat. With more than half of the species of penguins in decline – due to climate change, overfishing and habitat destruction – it is believed that through tourism the general public can be educated to understand how they may be able to help save the penguins. With thousands of people travelling to specific beaches to witness wild penguins, it should be questioned whether the penguins may be affected through the tourism industry in a variety of ways.

Is Wildlife Tourism Bad?

The term animal tourism is generally associated with negative connotations due to the fact that the majority of people link this to interactions with wild animals. However, this is not necessarily the case when discussing penguin tourism, meaning negative impact is often overlooked. When looking at recommendations to see penguins in the wild, it is common that the visit will consist of a guided tour with strict rules on keeping distance from the penguins and not touching them.

Gentoo Penguins at a tourist site in Antarctica (Source: Penguins International photo library)

But the penguins are walking toward me!

As CNN quotes, “penguins can be extremely curious, therefore they may approach people” (Spanne, 2019). This is most definitely true, especially of younger juvenile penguins. Villanueva, Walker and Beterellotti (2006) investigated the habituation of Magellanic Penguins to tourists through observing behaviour and measuring corticosterone secretion. The research compared penguins that lived in a tourist-visited area with those in an undisturbed area and found that there was no obvious negative effect on the penguins from tourists.

Tourists in Antarctica (Photo credit: Mel Sirois)

However, tourists do have the potential to make penguins sick

Research carried out in 2018 found that bacteria from tourists can be passed on to penguins in a “reverse zoonosis” (Rix, 2015). This research focused on faeces of over 666 birds found in Antarctica. Researchers have now become worried that the consequences of tourism on penguins could lead to numbers declining rapidly if a disease is spread (Bollevich, 2018). Cullen and Busch (2009) also discovered that unmanaged tourism can negatively affect the breeding success and survival of Yellow-eyed Penguins, potentially as a result of causing stress. Elsewhere, another study revealed that King Penguins showed signs of stress around humans, whether that being tourists or researchers, due to the disturbance of their “homes,” although it also found that once exposed to humans, the penguins become habituated to them (Rich, 1986).

So is tourism absolutely bad for penguins?

It is difficult to come to a concluding factor on whether penguin tourism has a negative effect on penguin health. When analysing research studies that have been completed, they all state a variety of different results, meaning that there cannot be a clear answer to the question. The only thing that can be stated is that it is the tour operator’s responsibility to ensure that the penguins are affected as little as possible through human presence. 

As discussed earlier, there has been evidence to support the chances of spreading disease across colonies in Antarctica. However, this research has only been limited to this area at current times, meaning that it may not be the case across other species of penguins. Each point around the effects of tourism on penguins has discussed a variety of species, meaning that a reliable conclusion cannot be made on how tourism affects penguins. Further research would need to be conducted on a particular species. Varying factors should also be investigated, such as comparing penguin behaviours dependent on distance kept by tourists. Information like this can then be used to put into place a best practise guide for tour operators, as this will ensure that the penguin’s welfare is affected as little as possible.

With 20%-40% of global tourism being animal attractions, it is understood that the income received via animals can have positive effects on the animals and local communities if used correctly (Action for ethical tourism, 2015). An example of how tourism has helped to save a species would be the tracking of gorillas across Uganda, Rwanda and Congo. There are strict rules put into place centred around tracking gorillas to ensure safety for tourists and animals. These types of tours have helped to increase numbers of mountain gorillas, with over 800 now found. Although research has produced data that proves tourists can pass on diseases to penguins, if strict regulations are put into place by tour operators, this should not cause any problems and can instead be a positive influence. 

The main aim of wildlife tourism should be to educate and conserve the species, with communication being a key factor in achieving success. If researchers piece together their findings and report this to local guides, then penguins should not be affected as much. Many tourists taking part in these tours are doing so because they want to witness an animal in the wild as it may be their last opportunity to do so. It is everyone’s responsibility to ensure that penguin species do not become extinct, so actions must be critiqued and communicated to ensure that it is not our last chance to witness penguins in their natural habitat.

What are your thoughts on visiting penguins after reading this blog? Please let us know. And please help us to continue to provide you with penguin news articles by donating to Penguins International.

Read more about penguins in some of our other blogs:

Like our penguin blogs? Sign up for our newsletter to get them right in your inbox!

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Action for Ethical Tourism (2015). Tourism Concerns. [Online] Guarantee (England). Available at: https://www.tourismconcern.org.uk/wp-content/uploads/2016/02/Animals-in- Tourism-|Web-Final.pdf [Accessed 30 Jun. 2019].

Bollevich, M (2018). Tourists may be making Antarctica’s penguins sick. [Online] Science | AAAS. Available at: https://www.sciencemag.org/news/2018/12/tourists-may-be-making-antarctica-s-penguins-sick [Accessed 1 Jul. 2019].

Busch, J. and Cullen, R. (2009). Effectiveness and cost-effectiveness of yellow eyed penguin recovery. Ecological Economics, 68(3), pp 762-776.

Rich, V. (1986) Falkland Islands: Opinions divided on penguin deaths. Nature, 322(6074) pp 4.

Rix, J. (2015). Should tourists be banned from Antarctica? [Online] BBC News. Available at: https://www.bbc.co.uk/news/magazine-30709924 [Accessed 1 Jul. 2019].

Spanne, A. (2019) 5 places to see penguins in their natural habitats. [Online] CNN Travel. Available at: https://www.edition.cnn.com/travel/article/penguins-viewing/index.html [Accessed 30 Jun. 2019]

Villanueva, C., Walker, B. and Bertellotti, M. (2011). A matter of history: effects of tourism on physiology, behaviours and breeding parameters in Magellanic Penguins (Spheniscus magellanicus) at two colonies in Argentina. Journal of Ornithology, 153 (1), pp 219-228.

What Lies Inside the Penguin’s Mouth

The inside of a penguin's mouth

What Lies Inside the Penguin’s Mouth

By Megan Spofford

I recall as African Penguin zookeeper how during feeding times, certain penguins preferred to be fed certain types of fish over others, and most preferred to be fed the head of the fish first (only 1 out of the 40 preferred to be fed tail first). If those penguins were offered an unpreferred item, or in an unpreferred way, the penguin would open its bill and sling its head quickly to the side to shake the fish I had given it from its mouth. In those instances, I had quick glimpses inside the mouth of the penguin, and honestly, it almost looked like something out of a horror story!

What the inside of a penguin’s mouth looks like.

A quick description of a penguin’s bill

From the outside, a penguin’s mouth, the bill, is one of its defining characteristics. There are variations in color for each species of penguin, which can be beautiful, like the King Penguin. The bills are hard keratin formations (keratin is the tissue that makes up human hair, giraffe hooves, and rhino horns). It has a hook on the end that helps a penguin to grip items. (This, of course, comes in handy since penguins do not have arms or hands like us.) There are also two nares on either side of the bill so the penguin can breathe with its bill closed, and which additionally serve as exit points for secretion of the highly concentrated salts they ingest.

What are those spiky things inside a penguin’s mouth?

By shifting focus to the inside of the mouth, we encounter that horror that I mentioned. Of course penguins do not have teeth, but it sure looks like their tongue and the roof of their mouth does! Those teeth-looking structures on the tongue and palate are actually comprised of soft keratin spikes called papillae. They appear sharp on the top, and curve backwards toward the back of the mouth.

What are the functions of those papillae on a penguin’s tongue?

First off, you may notice that those spiky papillae all point toward the back of the penguin’s mouth. Those work a bit like a fish hook. The penguin can grab onto a slippery fish and that food will now only move in one direction – down the penguin’s throat!

All tongues have papillae, including ours, but the penguin’s is more pronounced. It is believed that the reason for this is the function of the tongue. Animals that have “protruding papillae” are typically food collectors. Penguins certainly have pronounced papillae, and collect their food in the ocean! Tongues that have papillae that do not appear to protrude are said to use their tongue as a means to push the food around the mouth, and down the esophagus. Penguins can do this as well, although it has not been well documented. More than likely, the movement is limited, but it can move from side to side, and up and down. Finally, there are tongues that are meant to lie flatly so that food can travel down the esophagus when placed in the correct position. For penguins, all three of these functions seem to apply, with the latter being most applicable to chicks.

Anatomy of a penguin tongue

Underneath the papillae are fatty tissue, connective tissue, mucus glands, and serous glands. The salivary glands are present toward the back of the mouth, and secrete both mucus and serum. In a study conducted on Magellanic Penguin oral structures, salivary glands were present from day 1, but continued to develop, and secrete more beneficial mucus as the subjects got older. Most other birds maintain the same level of development of gland and mucus secretion from birth onward. It was once believed that seabirds who ingested foods from the marine environment would have smaller glands that secreted lesser amounts of mucins because the food was already lubricated by water. However, evidence from the study on Magellanic Penguins supports the theory that the salivary glands have a specific purpose other than to function based on their diet. The purpose could be for any of the following reasons: to break down food, protection from minor injuries, and keeping harmful organisms from creating disease in the mouth. 

What about penguin taste buds?

Most species of birds lack the gene receptors for sweetness, but penguins have even fewer taste buds. Some studies have found that only the receptor genes for salty and sour flavors showed up in penguin species. It’s hypothesized that umami, bitterness, and sweetness gene receptors evolved out of the penguin sequence, because their ancestors lived in cold environments where those receptors do not function well. 

How cool, (horrendous!), and unique is the penguin mouth?!?!

Do you want a mouth, or taste buds, like penguins? Did you like what you learned by reading this blog? Leave a comment below. And please help us to continue to provide you with penguin news articles by donating to Penguins International.

Read more about penguins in some of our other blogs:

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References:

Hall, Danielle, and Bill Fraser. “Penguins.” Ocean Find Your Blue, Smithsonian, 18 Dec. 2018, ocean.si.edu/ocean-life/seabirds/penguins.

Kobayashi, K, et al. “Fine Structure of the Tongue and Lingual Papillae of the Penguin.” Archives of Histology and Cytology, U.S. National Library of Medicine, Mar. 1998, www.ncbi.nlm.nih.gov/pubmed/9557966.

Paxton, et al. “The Leeds Histology Guide.” The Histology Guide, Faculty of Biological Sciences, University of Leeds, 1 Jan. 1970, www.histology.leeds.ac.uk/oral/tongue.php.

Samar, Maria Elena, et al. “Histochemical Study of Magellanic Penguin (Spheniscus Magellanicus) Minor Salivary Glands during Postnatal Growth.” Wiley Online Library, John Wiley & Sons, Ltd, 19 Nov. 1999, onlinelibrary.wiley.com/doi/pdf/10.1002/%28SICI%291097-0185%2819990201%29254%3A23.0.CO%3B2-7.

Yellow-eyed Penguins – one of the rarest penguins in the world

endangered species, what is the rarest penguins, how many types of penguins are there, where do penguins lives, what do penguins eat, what color eyes do penguins have

The Yellow-eyed Penguin – one of the rarest penguins in the world

by Georgia Podmore

The Yellow-eyed Penguin is one of the rarest penguin species in the world. It is found north of the Antarctic Ocean, along the coast of Southern New Zealand (Ellenberg, Mattern and Seddon, 2009). As the name suggests, the penguin is easily identifiable by the yellow colour around its eyes, along with a brightly coloured yellowish line that runs from its eyes round the back of the head.

Yellow-eyed Penguin characteristics

Like other penguins, the Yellow-eyed Penguin is carnivorous and preys on marine animals, such as crustaceans, cephalopods and fish. They are one of the larger species and can grow to approximately 75cm in height (Ellenberg et al., 2007). The penguins will breed once a year with their mate, who remain faithful to each other. The female will lay two eggs and both parents will help with incubating the eggs until they hatch. Once hatched, the chicks will stay with their parents until approximately twelve months old. The nesting sites for Yellow-eyed Penguins can be found in the forestry and shrubs that run alongside the southeast coast of New Zealand (Doc.govt.nz, 2019). Historically, the nesting sites have been undisturbed, however in recent years the penguins have had to face land predators. This has resulted in the species becoming an endangered animal with a wild population of less than 4,000 individuals (Yellow-eyed Penguin Trust, 2017).

Threats to Yellow-eyed Penguin populations

Predators

Yellow-eyed Penguins must deal with predators near their breeding grounds that are now beginning to hunt on their eggs. These predators include feral cats, stoats, ferrets and dogs (Ellenberg et al., 2007). On land, these predators are generally not a cause for concern for adult penguins. However, due to predation on their eggs, Yellow-eyed Penguin breeding success has been declining in recent years. Predators in the ocean include sharks and fur seals. The penguins have no defense against such large predators in the water, relying strictly on swimming speed and manoeuvrability, or escaping out of the water to dry land. Like all penguins, their colouration also helps disguise them from predators, as sharks and seals may find it difficult to see the penguins from below due to their white chest, or from above due to their black backs.

Human Interference

Humans have already disrupted Yellow-eyed Penguin populations by introducing some of the penguin predators into their areas. Another way in which humans have affected the number of penguins is through disturbance from the tourism trade (Ellenberg, Mattern and Seddon, 2009). Being a spectacular penguin to look at — along with its endangered status — brings in large numbers of people who want to see these animals in the wild before they’re gone. Research has shown that large numbers of tourists can be associated with reduced breeding success, along with decreased fledgling weight, which can then affect their survival rate in the first year (Mattern et al., 2007). These factors may be influenced due to stress on the adult penguins which may affect normal behaviour. 

Disease

As the climate is warming, disease is becoming a bigger issue for Yellow-eyed Penguins. Avian malaria was responsible for 29 deaths in 2018/19 (Yellow-eyed Penguin Trust, 2017), a large and impactful number for such a small population. With increased temperatures leading to increases in mosquito breeding, the threat for disease to penguins is expected to increase. Avian diphtheria is also affecting the species, which is commonly found in young chicks. Bacterial plaque forms in the mouth of the chick and is subsequently inhaled, which eventually causes aspiration pneumonia, a potentially fatal illness.

Stress can also cause penguins to become more susceptible to disease, which for the Yellow-eyed Penguin may be coming from increased threats and tourism. 

Deforestation

Habitat loss has become one of the main reasons the number of Yellow-eyed Penguins are decreasing (Mattern et al., 2007). In New Zealand, forests are being cleared to make way for field areas for grazing animals or homes. This is then resulting in increased pressure for the penguins as they attempt to find nesting areas. 

How can we help these extremely endangered Yellow-eyed Penguins?

Help for the Yellow-eyed Penguin started in the 1980s when the population was extremely low (Sue, 2019). Conservation organisations are focusing on protecting the forest and shrub land for the penguins to ensure they have the space to breed and build their nests, thousands of plants have also been planted around the areas for protection. Although this all sounds beneficial, help is still needed to protect more areas or to re-establish areas that have already been cleared.

In New Zealand, there is the Otapahi Reserve which is a protected area for the penguins, to ensure that they can live and breed without being disturbed by humans and predators. Dunedin Wildlife Hospital has also begun catching penguins with injuries and rehabilitating them. Veterinarian Lisa Argilla states, “We do what we have to do to save the species, as we cannot fix climate change and habitat destruction” (Biologicaldiversity.org, 2014)

There are a large amount of conservation groups and rehabilitation centres now working to support the Yellow-eyed Penguins and to help increase the population. Every effort is being made to ensure that the population is protected, and with support from the public we can all strive to make the maximum impact and hopefully save the Yellow-eyed Penguin from extinction.

Did you know about Yellow-eyed Penguins? And how rare they are? Did you like what you learned by reading this blog? Leave a comment below. And please help us to continue to provide you with penguin news articles by donating to Penguins International.

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Reference List

Biologicaldiversity.org. (2014). Yellow-eyed penguin. [online] Available at: https://www.biologicaldiversity.org/species/birds/penguins/yellow-eyed_penguin.html [Accessed 31 Aug. 2019].

Center for Biological Diversity (2019). Yellow-eyed Penguin. [image] Available at: https://www.biologicaldiversity.org/species/birds/penguins/yellow-eyed_penguin.html [Accessed 31 Aug. 2019].

Doc.govt.nz. (2019). Yellow-eyed penguin/hoiho. [online] Available at: https://www.doc.govt.nz/nature/native-animals/birds/birds-a-z/penguins/yellow-eyed-penguin-hoiho/ [Accessed 31 Aug. 2019].

Ellenberg, U., Mattern, T. and Seddon, P. (2009). Habituation potential of yellow-eyed penguins depends on sex, character and previous experience with humans. Animal Behaviour, 77(2), pp.289-296.

Ellenberg, U., Setiawan, A., Cree, A., Houston, D. and Seddon, P. (2007). Elevated hormonal stress response and reduced reproductive output in Yellow-eyed penguins exposed to unregulated tourism. General and Comparative Endocrinology, 152(1), pp.54-63.

Mattern, T., Ellenberg, U., Houston, D. and Davis, L. (2007). Consistent foraging routes and benthic foraging behaviour in yellow-eyed penguins. Marine Ecology Progress Series, 343, pp.295-306.

Sue, M. (2019). Penguins: Yellow-eyed Penguins – Megadyptes antipodes. [online] Penguins.cl. Available at: http://www.penguins.cl/yellow-penguins.htm [Accessed 31 Aug. 2019].

Yellow-eyed Penguin Trust. (2017). Distribution and habitat. [online] Available at: https://www.yellow-eyedpenguin.org.nz/penguins/distribution-and-habitat/ [Accessed 31 Aug. 2019].

Penguins are overheating! Yep, you read that right!

Penguin skin showing feather density

Penguins are overheating! Yep, you read that right!

By Beth Storey-Jones

What do you imagine when you think of penguins? 

  • Highly adapted?
  • Caring parents? 
  • Amazing swimmers? 
  • Looking fly in their tuxedos? (no pun intended)

Well you would be 100% correct on all accounts. You might also worry about how they may struggle to keep warm? In fact, this isn’t their primary issue. They’re actually more at risk of overheating! Yes, I did say overheating. This is a real problem and is becoming detrimental to penguin populations. Let me explain!

Brief penguin anatomy and physiology lesson

First, let’s take a brief look at a penguin’s anatomy and physiology. They are aquatic, built for life at sea. To allow them to thrive in the water, warm-blooded animals need to be well insulated. Whales have blubber, seals have thick fur pelts, but birds have neither. Evolutionarily speaking, birds avoided adaptations that would hinder flight. So, penguins have had to use pre-existing characteristics and tweak them to survive in their niche, this being their feathers.  As a result, these feathers are short, ridged and interlock [1] to form an air trap (figure 1). Which is equivalent to a dry suit. Any heat obtained by the bird is kept in between the base layer of the feathers and the top layer of the skin, and works well as an insulator when in the water. The trouble comes when this same heat is not released, as when they return to land.

Fig. 1 Penguin skin showing feather density [1]

Penguin Distribution – Where do they live?

Fig. 2 Penguin Range Map [2]

Contrary to popular belief, most penguin species live in temperate and even tropical zones, not Antarctica (Fig. 2). Consider the Little Blue Penguin, who breeds up and down the coasts of Australia and New Zealand [2]. They often only come ashore once the sun begins to set. A more popular species, the Galapagos Penguin, avoids direct sunlight by creating nesting areas in shaded lava rock cracks. Water temperature can also be as high as 30oC (86.0°F) around the equator [3] and for a bird that has to maintain an internal body temperate of 39oC (102.2°F) this can be challenging. With their feathery armour only just able to regulate this temperature, prevention methods aren’t always the best medicine.

So, how do penguins combat hyperthermia? To answer this question in short, thermoregulation adaptations. It’s really interesting, so I’ll elaborate! You may have noticed that quite a few bird species have naked legs or webbed feet, or both. These areas of the body house complex blood vessels which can constrict to control the amount of heat loss when cold or expand to lose heat when the animal is too hot, comparable to a radiator [3]. Penguins such as the Humboldt Penguin also have featherless faces. Behaviourally, penguins pant. Which evaporates the body’s moisture while using up body heat to do so. Much like your dog, when he’s retrieved his favourite tennis ball for the 100th time. Penguins will also hold their flippers out to the side to allow breezes to cool them down even further.

Chicks at risk

Penguin chicks are also at risk of overheating. Their soft down is even more efficient at heat retention. While unable to thermoregulate, chicks are sheltered from the sun by their parents. Unlike the adults, their flippers are also covered in insulating down. So, the babies have to rely on their disproportionately large (and cute) feet (Fig. 3) to act as a personal radiator [3]. On exceptionally hot days, juveniles have been observed essentially laying like a starfish on the ground to expose their feet. Some species will even stand in water. 

Fig. 3 The extra-large feet of a penguin chick [3]

Challenges ahead…

So far, it has been explained that heat regulation is a bit of a challenge for the penguin. That is without even taking into consideration our global warming crisis. I know, I know, everyone is talking about it. But it is a vital element to consider in the lives of our beloved penguin friends. The finely tuned adaptations we have talked about did not happen overnight. It was through the millenia-long trial and error process of evolution and will still be ongoing today. These adaptation changes aren’t necessarily a problem, but it’s the small window of opportunity that these animals (as well as other species) have to do it in when temperatures rise quicker than evolution. Sadly, this is where the detrimental part comes in. Sea temperatures are increasing. Penguin chicks are struggling to survive due to poor food quality and quantity from these temperature increases[4]. The warmer climes seen in Antarctica recently are causing unprecedented rainfall and the melting of potential snowfall. This can be damaging to eggs that must be kept dry and warm. And the chicks may also become muddy and wet and can succumb to hypothermia because their down feathers are not waterproof[4].

Let’s bring it all together. Penguins live in water. They inhabit not only the harsh, dry and cold parts of the world, but surprisingly also some of the hottest. They have finely-tuned mechanisms to allow them to do so. Such as radiators for feet and dense plumage for when they need to stay warm. But these adaptations are so specialised to their surroundings, that any changes can be fatal. With sea temperatures rising, food availability and competition is high, as well as the risks of chicks being exposed to hyper or hypothermia. This brings a bit of a chilly end to an extremely cool topic!

Thinking of penguins in general, do you think they would overheat? Did you like what you learned by reading this blog? Leave a comment below. And please help us to continue to provide you with penguin news articles by donating to Penguins International.

Read more about penguins in some of other blogs:

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Reference List

  1. DeNapoli, D. 2010. The Great Penguin Rescue. New York. Free Press. 
  2. Muller-Schwarze, D. 1984. The Behaviour of Penguins – Adapted to Ice and Tropics. New York. State University of New York Press
  3. Kaiser, G. 2007. The Inner Bird: Anatomy and Evolution. Vancouver. University of British Columbia. 
  4. Sidder, A. 2016. Antarctica Could Lose Most of Its Penguins to Climate Change. [online]. National Geographic. Available from: https://www.nationalgeographic.com/news/2016/06/adelie-penguins-antarctica-climate-change-population-decline-refugia/ [Accessed 24 October 2019].

Figures

  1. National History Museum. 2018. Ever wondered how Emperor Penguins survive temperatures of -60 degrees centigrade? Their feathers are densely packed as these photos show but as researcher Cassondra L. Williams and colleagues discovered there is more to the story than meets the eye. [online]. Twitter. Available from: https://twitter.com/nhm_oology/status/1022076201828012032 [Accessed 24 October 2019].
  2. Kikkawa, E., Tsuda, T., Sumiyama, D., Naruse, T., Fukuda, M., Kurita, M., Wilson, R., LeMaho, Y., Miller, G., Tsuda, M., Murata, K., Kulski, J., & Inoko, H. 2009. Trans-species polymorphism of the Mhc class II DRB-like gene in banded penguins (genus Spheniscus). Immunogenetics. 61, 341-352.
  3. Tennessee Aquarium. 2017. Call It “Sasquawk”: Big Feet a Distinct Feature of the Aquarium’s Newest Penguin Chick. [online]. Tennessee Aquarium. Available from: https://www.tnaqua.org/newsroom/entry/call-it-sasquawk-big-feet-a-distinct-feature-of-the-aquariums-newest-pengui [Accessed 24 October 2019].

Have Penguins Ever Been Able To Fly?

Humboldt Penguin showing off its flippers and swimming ability.
(© Martin Franklin/ZSL)
Humboldt Penguin showing off its flippers and swimming ability.

Have Penguins Ever Been Able To Fly?

by Martin Franklin

Swimming is normal for me. I’m relaxed. I’m comfortable, and I know my surroundings. It’s my home.” (Michael Phelps, most decorated Olympian of all time).

Swimming is a confusing sport. Sometimes you do it for fun, but then other times you do it to not die. And when I’m swimming, sometimes I’m not sure which one it is. You have to go by the outfit. Pants – oh oh! Bathing suit – ok! Naked – we’ll see!” (Demetri Martin, comedian).

Penguin conservation is imperative!

(© Martin Franklin/ZSL)
Humboldt Penguins with a view of their flippers in the water.

In the course of my work as a zookeeper at ZSL London Zoo (a charity which supports animal conservation projects all over the world), I frequently get asked some pretty odd (often brilliant) questions. Recently two 6- or 7-year-olds asked me, “Have penguins ever been able to fly?” (A great question, I thought). Although we ended up talking about traits these children had inherited from their grandparents, I ultimately utterly failed to explain in simple enough terms to them how evolution works – entirely mea culpa. (Incidentally, for thoroughly clear and persuasive introductions to the facts and mechanisms of evolution, I’d highly recommend reading both Coyne1 and Dawkins2).

This incident did, however, prompt me to write this piece. Of course, penguins, as we understand and envisage them, have never been able to fly. But their ancestors, from whom they evolved, unquestionably could. The real question is to ask what pressures or opportunities caused that change.

Why do penguins swim instead of fly?

First, however, a quick look at flightlessness in birds generally. Although flying has proved advantageous to most bird species (and has thus been retained), a wide range (in terms of size, geographical spread and ecology) have evolved to discard the power of flight once possessed by their ancestors. These include:

  • “Ratites” (i.e. ostriches, rheas, emus, cassowaries and kiwis, plus the now extinct moas and elephant birds), which lack a keel (ridge) on their sterna (breastbones) onto which to attach flight muscles. 
  • Numerous waterfowl (Anseriformes) (e.g. Aukland Teals and Campbell Teals).
  • Two species of grebe (Podicipediformes) (i.e. Junin Grebes and Titicaca Grebes).
  • One of the pelican/cormorant group (Pelecaniformes) (i.e. flightless cormorants). 
  • One of the parrot group (Psittaciformes) (i.e. Kakapos). 
  • Numerous rails (Gruiformes) (e.g. Calayan Rails and Pink-legged Rails).
  • A variety of now extinct birds, including from the: pigeon and doves (Columbiformes) (e.g. Dodos); gamebirds (Galliformes); hoopoes (Coraciiformes); birds of prey (Falconiformes); owls (Strigiformes); nightjars (Caprimulgiformes); perching birds (Passeriformes); and auks (Charadriiformes).

Many of these flightless species come/came from remote, predator-free, food-abundant islands, which helps explain why they lost the ability to fly. It is “expensive” (in terms of energy required and lost other opportunities) for birds to maintain the necessary physical attributes needed for flight (e.g. large, calcium-rich, keeled breastbones and large chest muscles). Therefore, if it’s no longer necessary to fly to avoid predation or hunt, natural selection frequently results in less investment in such “expensive” materials/attributes.3

Flightlessness exists in many birds besides penguins

Flightlessness has also evolved independently in:

  • large-bodied, herbivorous birds (e.g. ostriches, emus, cassowaries, moas and elephant birds), as a diet of high-volume low-quality vegetation favours developing a large body, which in turn increases the challenges of maintaining the apparatus needed for flight; 
  • several foot-propelled diving birds (e.g. flightless cormorants), as these evolved to have powerful, paddle-like legs and feet (so their wings and chest-muscles became increasing less important for locomotion, and accordingly regressed); and
  • penguins (i.e. wing-propelled divers, that in water use their feet as a rudder, rather than for propulsion). These are by far the largest bird family whose entire members are flightless.4

The transition from flying birds to wing-propelled divers was a gradual process which started around 65 million years ago for penguins, and would have involved an intermediate stage whereby its ancestors could use their wings for both flying in the air and diving/swimming underwater (much as Razorbills, for example, do today). These ancestors were probably seabirds similar to modern diving petrels.

Strategies for a bird to choose swimming vs. flying

One of two strategies can be adopted once such a bird reaches a critical size of around 1kg (above which the size of wing needed for flying becomes too large for efficient swimming). Either: 

(1) the wings can be kept solely for flying, and the feet/legs can be used for underwater propulsion (as observed in most modern ducks and cormorants); or 

(2) aerial flight can be abandoned in return for superior underwater swimming (as happened with penguins).4,5

Gradually, therefore, as this ancestor fared better swimming underwater than flying above it:

  • No longer constrained by the necessity of flying as well as swimming, it was able to increase its weight. (One now-extinct penguin species, Anthropornis nordenskjoeldi, weighed around 135kg, and the modern Emperor and King Penguins are also relatively large animals). 
  • Slim wing bones became increasingly shorter and heavier, eventually resulting in the flat, broad (and less flexible) flippers sported by modern penguins.
  • Other related adaptations developed, including, for example, a hydrodynamic body shape and denser bones (unlike flying birds’ air-filled bones), meaning penguins are not overly buoyant. 

As a result, by 55 million years ago, penguins were completely flightless but thoroughly adapted to life in water.4,5

(© Martin Franklin/ZSL)
Streamlined bodies and rigid, flat flippers allowing strong swimming ability in penguins.

The adaptations that penguins have developed over thousands of years never ceases to be fascinating. Tell us your thoughts in the comment sections below. And please consider assisting with our conservation projects and helping us to continue to provide you this information by donating to Penguins International.

Read more about penguins in some of other blogs:

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References

1 Coyne, J. A. (2009). Why Evolution is True. Oxford University Press: Oxford.

2 Dawkins, R. (2009). The Greatest Show on Earth. Transworld Publishers: London.

3 McNab, B. K. (1994). Energy Conservation and the Evolution of Flightlessness in Birds. The American Naturalist. Vol. 144, no.4, 628-642.

4 Gill, F. B. and Prum, R. O. (2019). Ornithology. (4th edition). W. H. Freeman and Company: New York.

5 Lynch, W. (2007). Penguins of the World. A&C Black Publishers Limited: London.

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phone: 628-400-7301

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