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Cold Feet: Why Don’t Penguin’s Feet Freeze?

Adelie Penguins at McMurdo

Cold Feet: Why Don’t Penguin’s Feet Freeze?

by Sian Liversage

We all know that penguins endure and survive freezing temperatures in the Antarctic, these can range as low as -70˚C in the centre to -20 ˚C around the coast. Their bodies stay warm due to their insulating layers of blubber which lies just beneath the skin. However, their webbed feet are continually in contact with snow and ice, and yet somehow they manage to stay free from frostbite. So, it begs the question: Why don’t their feet freeze?

Penguins have special adaptations to keep their feet from freezing

Like many other species around the world, penguins have adaptations to avoid losing too much heat and to preserve a central body temperature. Penguin feet make it problematic to maintain that perfect body temperature of 40°C since they are constantly exposed to the elements; their feet cannot be covered with blubber or feathers like their bodies are, and together they create a large surface area exposed to the cold. But they need their feet so they can walk around the icy surface without slipping, and also so they can steer themselves when swimming. 

A variety of penguins have developed behaviours that enable them to keep their feet warm. For example, Emperor Penguins hunch down so their bellies and feathers cover their legs, and they also rock back and forth onto their heels to lift their feet off the ice, therefore reducing contact time on the ground.

Penguins keep their feet from freezing not only behaviourally, but also through internal mechanisms

This is not the only way penguins avoid getting cold, however. They have evolved remarkable physical attributes too that make them perfectly adapted to their environment. There are two hidden mechanisms going on inside those legs and feet.

First, a penguin can control the rate of blood flow to the feet by varying the diameter of arterial vessels supplying the blood. During cold conditions, the flow of blood is reduced to hold onto heat. In winter, penguins will keep their feet a degree or two above freezing which reduces the chance of heat loss and avoids getting frostbite.

Chinstrap Penguins walking on the snow

And, of course, not all penguins live in places where their feet get cold

Not all penguin species live in freezing conditions though. Some species like Galapagos Penguins live in scorching sun and heat and thankfully their specialised heat exchange system also serves as a vital outlet for when their bodies become too warm. Blood vessels in the penguin’s feet expand, doing the opposite of what they do when they are cold. This allows an increase in blood flow, which in turn enables heat loss from the body. You may see penguins lying on the ground with their feet in the air and their flippers out to the sides to speed this process up and get rid of excess body heat.

Magellanic Penguins in the desert in Argentina

Humans can also do what penguins do with their feet (to some extent)

Penguin feet closeup
Close up of the bottom of a penguin’s feet

Amazingly, humans can also restrict blood flow to their extremities too. Our hands and feet will go white when they are freezing due to less blood circulating to them; blood is being redirected and prioritised to go to the core of the body where the vital organs will be kept warm. On the other hand, when we are warm our hands and feet will turn pink which is our body trying to cool us down. Controlling blood flow is very sophisticated and involves the hypothalamus, the nervous system and endocrine systems all working together to function properly.

Secondly, penguin legs work like a heat exchange system; blood vessels to and from the feet are narrow and woven closely together, which cools the blood from the body on the way to the feet and vice versa when the blood returns to the body. Therefore, their feet receive cool blood instead of warm blood, as this means less heat is lost while the body continues to maintain that toasty 40°C. 

These adaptations show just how truly extraordinary penguins are; generations have survived the worst conditions nature could throw at them. These cold-adapted species live a challenging life, walking 100s of kilometres to feeding grounds, surviving snowstorms, and standing for weeks on ice while incubating an egg, and at the same time maintaining a warm body core temperature. Despite all these potential setbacks, their incredible feet and overall mechanisms to survive are still yet to be hindered by Mother Nature.

Penguins are amazing birds that have adapted ways to live in extreme environments. Have you ever seen some of these penguins in the wild? Tell us about it in the comments below. And please assist with our conservation projects and help us continue to provide you this information by donating to Penguins International.

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References:

  1. Encyclopedia Britannica Blog. 2011. Penguin Feet: Avoiding Frostbite in the Antarctic. Webpage: http://blogs.britannica.com/2011/01/penguin-feet-avoiding-frostbite-in-the-antarctic/
  2. How Stuff Works. 2019. Why Penguin Feet Don’t Freeze. Webpage: https://animals.howstuffworks.com/mammals/why-penguin-feet-dont-freeze.htm
  3. New Scientist. 2006. Why don’t penguins’ feet freeze? And 114 other questions. P. 47-77

Penguin Record Breakers

Emperor Penguin with Mount Erebus

Penguin Record Breakers

by Martin Franklin

At 100-130cm long and 22-40kg in weight, the Emperor Penguin is by far the largest of all the penguins. (This is, incidentally, only a little smaller than champion gymnast Simone Biles, whose height is 142cm and weight 48kg). But do the Emperor Penguin’s height and weight advantages translate into record-breaking penguin performances?

(1) Greatest Diving Depth – Emperor Penguin vs. Human

Alexey Molchanov holds the current human world record for the deepest single-breath dive (with fins, and without use of weights or inflation devices). He managed 130m. (Without fins, William Trubridge holds the record, at 102m). This equates to the Emperor Penguin’s preferred “average” dive depth, but it can easily dive to 400m, and has even been recorded at a depth of 564m. With a pressure at such depths of up to 30 times that at the surface, and no other penguins able to descend so deep, the Emperor Penguin is unquestionably the champion deep sea diver.1,2

(2) Longest Time Spent Under Water for Emperor Penguins

The human record for this is currently held by Stephane Mifsud, who lasted 11m 35s. This, however, was stationary and in a shallow swimming pool, meaning his physical exertion was negligible, and he was unaffected by water pressure associated with water depth. Again, the Emperor Penguin beats this hands (or perhaps flippers) down: It prefers short dives of 3-6 minutes, but can stay under water for up to 22 minutes, which is longer than any other bird can manage.1

Southern Rockhopper Penguins diving into the water

(3) Fastest Swimming Speed of Emperor Penguins

The human world record holder in the 100m freestyle is Cesar Cielo, with a time of 46.91s, which equates to around 4.8mph (7.7kmph). The unofficial fastest recorded penguin to date (though others could be faster) is the Gentoo, at around 22mph (36kmph). That’s around 5 times faster than the fastest human.

Gentoo Penguins after a day of fishing

Penguins achieve these incredible speeds due to their unique anatomy, which includes:

  • A torpedo-like body shape (including legs placed far back on their bodies) which results in remarkably little drag (the legs only being used for steering when swimming);
  • Flattened and rigid wing bones, the arrangement of which (unlike in flying birds) create significant forward propulsion on both the up and down-stroke;
  • A silky outer layer of feathers; and
  • Heavy (non-pneumatic) bones, so the birds are not fighting buoyancy in the way flying birds would.

Penguins also have handy built-in “goggles”, meaning they can see well on both land and in water, as they possess:

  • Nictitating membranes (i.e. a transparent inner eyelids which can be drawn over the eyes);
  • Flat corneas (the transparent front part of the eyes), which reduce refraction (light changing course in different ways in different media); and
  • Strong focusing muscles (allowing them to change their lens shapes as required).1, 3

(4) Competitive Eating (and Remarkable Egg-Care)

Penguins can eat an astonishing quantity of food very quickly, and their consumption increases markedly at particular times, i.e.:

  • Immediately before they moult (during a moult, which typically lasts a few weeks, they are no longer water-proof or able to thermo-regulate effectively, and thus cannot go fishing at sea);
  • When they have chicks to feed (which are fed regurgitated food);
  • In the case of Emperor Penguins, immediately before they start their long (up to 125 mile/200km) “march” to form breeding colonies. This is followed by the males taking on egg-incubation duties (which last for 62-67 days without food and in temperatures as low as minus 60oC, unassisted by their female partners, and with only the body heat of other males with whom they huddle to help stay warm).

This feat of the Emperor Penguin breaks numerous records, including:

  • Being the only penguins to breed during the Antarctic winter;
  • This being the most intense cold experienced by any warm-blooded animal;
  • This being the longest continual incubation period of any bird (although kiwis and great albatrosses incubate for 71-84 days, they leave their nests to feed)2;
  • Males being able to regurgitate a protein-rich stomach secretion to feed their chicks for up to 10 days (if the females don’t get back to share chick-feeding duties in time);
  • Being the only birds (technically) never to touch land (as they generally form their breeding colonies on winter sea ice).1

Adélie Penguins have been reported as able to eat 25g of krill per minute (which equates to around 0.5% of their body weight per minute).3 This species has also been  reported as eating around 800g of food per bird per day (which equates to around 16% of their body weight).4 In terms of weight alone (not calorific content), this is broadly equivalent to an average American man eating two 240g “Big Mac” hamburgers per minute, or 59 “Big Macs” per day.

Two colleagues tell me anecdotally that they once witnessed a chick-raising pair of Humboldt Penguins at ZSL London Zoo rival even the Adélie Penguins mentioned above. In just a few minutes, I am told that these birds (a female named Heidi and a male named Lars, pictured) each ate approximately 80-100 sprats (weighing around 840g). Given these penguins’ normal weights of around 4½kg each, this equates to them each eating around 19% of their normal body weights in one brief sitting.

 

Of course, Heidi and Lars were behaving naturally and appropriately, given their own nutritional requirements and those of their chicks at that particular time. I only wish I could claim a similar excuse myself in respect of my own occasional over-indulgences.

Lars and Heidi – Humboldt Penguins at ZSL London Zoo with (seasonal dependent) impressive appetites

© 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 are amazing animals with even more amazing adaptions that help them live in extreme places. Like this story? Have a story of your own? 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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References

1 De Roy, T., Jones, M. and Cornthwaite, J. (2013). Penguins: Their World, Their Ways. Bloomsbury Publishing: London.

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

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

4 Culik, B. M. (1993). Energetics of the Pygoscelid penguins. Habilitation thesis. University of Kiel.

Penguins in Captivity: Keeping them happy

Southern Rockhopper Penguin

Penguins in Captivity: Keeping them happy

By Sian Liversage

It seems that no matter what age you are, whether a child or an adult, one of the most popular and interesting animals to see when visiting a zoo or an animal attraction are the penguins. People have certainly anthropomorphised this species because of the way they look and behave; a good example of this is how they are often compared to a small human wearing a tuxedo. Their waddling gait, clumsy nature and charismatic personalities make them an ideal species to have in captivity, simply to bring the people in. But should they be kept in captivity in the first place?

There is definitely a balance to keeping penguins happy and healthy in captivity

We can’t hide the fact that there are some negative sides to life while living in the care of humans, especially if animals are mistreated or not appropriately housed. Penguins are no different when it comes to struggling in a captive situation.

In one facility, staff had to administer medication to their Humboldt penguins after they showed signs of stress attributed to the difference in local weather that was very different to their natural climate.

Stress can lower a penguin’s immune system, which could cause them to be more vulnerable to diseases, especially if they are kept in poor conditions. Enclosures that are small, with small pools, means that penguins cannot display their natural behaviours, which in turn will increase their stress levels. Another facility nearly ten years ago had several Humboldt Penguins die of infections from unknown causes. This could have been attributed to stress from living conditions or lack of staff knowledge, or any other number of reasons.

Despite the best intentions of an animal keeper, things don’t always go smoothly. For that reason, we promote AZA accreditation in the U.S. and BIAZA membership in the U.K. for facilities that meet strict guidelines for animal management and care. The standards held by facilities with this oversight will ensure the best care is given to all of their animals. 

Animal care and management goes beyond best practices, however. The penguins need to be kept engaged and in an environment that promotes enrichment.

Zoo enclosures have advanced dramatically in keep penguins happy and healthy

Zoo enclosure designs have come a long way since the bare concrete space that animals used to live in, now providing an engaging, healthy sanctuary for penguins. Zoos and aquariums also play a key role towards conserving endangered species too, of which there are a large proportion of penguins under this category. Likewise, many zoos and aquariums aim to promote conservation work, educate the general public, and support wildlife projects. All of these categories merge to create a standard of welfare, which means that penguins which are kept in captivity are given the utmost care. These standards are in place to allow the animals to develop in a healthy environment as similar to their natural habitat as possible.

New enclosure designs promote more natural behaviours in penguins

The Detroit Zoo recognised that their penguins needed something more in their enclosure, so they replaced a 6-foot deep pool with a 25-foot deep pool. The penguins ended up spending extra time in the water than previously, showing the zookeepers that this new change enhanced their lives that much more. The penguins spoke and their keepers listened.

Flagship species, like penguins, will draw crowds in, helping to raise their profile. This will in turn fund conservation efforts to help protect the species in the wild. So, keeping them in an enclosure that promotes their natural behaviour is vital not only for giving them a stress-free life, but also for educating the general public on their behaviours and the conservation work that is ongoing throughout the world.

Humboldt Penguin stands on the edge of its pool. Photo found at: https://www.penguins-world.com/penguins-in-captivity/

No matter what evidence is put forward though, animals in captivity whether it be focusing on penguins or not, will continue to be a controversial issue that is widely discussed. From the evidence shown in this blog, it seems that as long as penguins can behave naturally, they are able to live a long happy life in a human made environment without predators. The efforts that zoos and parks will go to nowadays to keeping their animals stress free is astounding, and I think it’s safe to say that people have learned from the past and will continue to learn the needs of their animals for the future. 

Pro/con, zoos are helping penguins feel like they are more in their natural habitats while in captivity, but they will always feel do better when free. Please help us continue to provide you this type of information by donating to Penguins International.

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References:

DW Made for Minds. 2017. Should penguins be an animal attraction? Webpage: https://www.dw.com/en/should-penguins-be-an-animal-attraction/a-38557239

Penguins World. 2017. Penguins in Captivity. Webpage: https://www.penguins-world.com/penguins-in-captivity/

In defence of zoos: how captivity helps conservation. 2016. Webpage: http://theconversation.com/in-defence-of-zoos-how-captivity-helps-conservation-56719

Why are we still lacking effective conservation measures for penguins?

Southern Rockhopper Penguin

Why are we still lacking effective conservation measures for penguins?

by Nataly H. Aranzamendi

Penguins are in trouble. Despite being loved by people and being the target of large amounts of research, many penguin species are currently classified in an endangered category. In order to protect these amazing birds, penguin conservation efforts need to be initiated, strengthened and supported.

Penguin conservation is imperative!

More than half of the 18 penguin species are considered to be in decline and their populations have not recovered since penguin conservation efforts began1. Even for those species that are showing positive signs of recovery, multiple threats still make their situation at jeopardy. 

To discuss and underline which are the most immediate conservation needs to protect penguins, a group of scientists working with penguins, the IUCN Penguin Specialist Group, held a workshop and has published their most relevant conclusions1. Following are some take home messages from this work. 

What are threats to penguins?

Using a pairwise ranking approach, the scientists ranked penguins according to the most pressing global threats existing at the moment for all species. This approach gave a ranking of those species that needed more conservation and research. 

Another ranking was done for those penguins that need the most urgent conservation measures and immediate political intervention. Either because they are species experiencing rapid population declines or species with extremely limited distribution ranges. Three species were at the top of the ranking: African Penguins, Galapagos Penguins and Yellow-eyed Penguins. 

An Endangered African Penguin

Decreasing penguin populations

African Penguin populations have decreased since the early 1900s to only 21,000 pairs left. Their decline has been most likely caused by a lack of food as a byproduct of changes in climate and overfishing. Petroleum pollution and predation have had a major toll on this species as well. The IUCN Penguin Specialist Group has suggested that a network of Marine Protected Areas could offer protection for the majority of these birds, although the protection may not help during all life stages. 

Galapagos Penguin populations have suffered extreme number fluctuations, in relation to El Nino events. This species can skip breeding when food is scarce. That, in combination with limiting cavities for breeding, and the presence of invasive predators, has vanished any hopes of quick recovery. For this penguin with a very limited geographical range, the management of fisheries is crucial, since it will guarantee food at tough times. At the moment, less that 1% of the marine reserve around Galapagos is closed to fishing. 

The Yellow-eyed Penguin has suffered steep declines and currently only 1,700 pairs are left. This species faces several threats: introduced predators, environmental change and interaction with humans and fisheries. Managing these threats in conjunction could offer better perspectives for their future. 

Endangered Galapagos Penguins
An Endangered Yellow-eyed Penguin

Marine Reserves are the most powerful tool for penguin conservation

From all the measures discussed by the group of specialists, Marine Reserves were ranked as the most valuable tools for conservation existing to date. The creation of such reserves will allow management of several threats simultaneously, including those threats created by direct interaction with humans (i.e. tourism).  

But why has penguin conservation not moved faster in the last decades? The group agreed that most of the limitations are in relation to the penguin’s biology and funding problems. 

Penguins are colonial long-lived species that can potentially move beyond a country’s boundaries. This means that to effectively study them, long-term funding to follow individuals throughout their lives and international collaboration at many levels are needed. Such factors constitute the most limiting issues at the moment. 

Lack of long-term funding does not allow long-term monitoring of most populations. Moreover, due to practical reasons, most penguins are monitored only when they breed, leaving gaps of information about what they do in the non-breeding season. 

The non-breeding season, as well as the juvenile stage, are key elements to monitor, since it is at those stages that increased mortality occurs, which eventually would have consequences for population trends. 

Effective protection of international waters is also an issue. At the moment, only 2% of the ocean is protected, while the goal established by international agreements is to reach 30% of ocean protection. A goal that seems unreachable right now. 

To successfully protect penguins requires collaboration and communication between stakeholders: groups of scientists, legislators, NGOs, fisheries and local population. Without such collaboration, any ambitious conservation goal for penguins will not be reached. 

Action to protect our treasured penguins is needed now, because penguins are running out of time. It has become everyone’s work to take action for the penguins and their future.

As you can see, there’s still a lot of work that must be done to protect and conserve penguins. Please assist with our own conservation projects and help us continue to provide you this information by donating to Penguins International.

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References

  1. Boersma, P. D., Borboroglu, P. G., Gownaris, N. J., Bost, C. A., Chiaradia, A., Ellis, S., … & Waller, L. J. (2019). Applying science to pressing conservation needs for penguins. Conservation Biology 10.1111/cobi.13378.

The Antarctic Treaty Helps Antarctic Penguins

Antarctic Treaty, antarctica, Antarctic penguins, penguins, when was the Antarctic Treaty signed, what did the Antarctic Treaty do, how many countries signed the Antarctic Treaty, Environmental Protocol protects penguins, Environmental Protocol of the treaty

The Antarctic Treaty Helps Antarctic Penguins

By Megan Spofford

What is the Antarctic Treaty?

The Antarctic Treaty is a document comprised of 14 articles outlining laws about how to govern Antarctica, and was originally signed into agreement in 1959 (but officially enacted in 1961) by 12 different countries. These countries agreed to manage the location only with peace, and as a place for scientific research where ideas were shared amongst each other. Some of the countries had already lay claim to certain regions in Antarctica before the Treaty was signed, and although those particular regions may still recognize those claims individually, as a whole, they are not controlled by any particular nation per the Treaty. The area of coverage this pertains to is anything below 60º S latitude.

Signing of the Antarctic Treaty on December 1st 1959
Source: Antarctic Treaty Image Bank
https://atsimagebank.omeka.net/items/show/9

Who participates in the Antarctic Treaty?

As of 2019, there are currently 54 recognized countries that participate in the governance of the Antarctic Treaty. These comprise of the original 12, and 42 more who were added throughout the years (a full list is in the image below). Not all of the participatory countries are actively involved in research on the continent, however. While 54 countries may not sound like many in the grand scheme of things, in reality it truly is a substantial number because all the countries that are part of the treaty (regardless of conducting research or not) represent at least ⅔ of the world’s population. The leaders from each of the signatory countries engage in yearly meetings to address matters that concern the Treaty.

"Antarctic Treaty". United States Department of State. April 22, 2019.
Signing of the Antarctic Treaty on December 1st 1959
Source: Antarctic Treaty Image Bank
https://atsimagebank.omeka.net/items/show/9
Map of Territorial Claims in Antarctica
Source: CIA World Factbook

The Protocol on Environmental Protection to the Antarctic Treaty

An especially important meeting occurred in 1991 in Madrid where Article 12 was addressed. This article explained that the limitations of the Treaty should be reassessed after 30 years (remember this Treaty was enacted in 1961!), and that if any of the participating entities were disgruntled with any part of it, the committee needed to address it. This is when the Environmental Protocol happened to be drafted. The Environmental Protocol set forth the recognition of Antarctica as a nature reserve, and protects the natural resources and native species of the area. This is the portion of the protocol that protects Antarctic penguins! It was officially enacted in 1998, and since then, revisions have been added to the protocol to better specify its purposes, or extend its reach.

How the Environmental Protocol protects penguins

The Environmental Protocol covers Antarctic flora and fauna (the fauna portion includes penguins). In particular, it gives native penguins and other animals the status of “specially protected species,” and explains that they cannot be removed, injured, killed, or disrupted by human activity (such as by motorized vehicles or pollution of the environment from waste). In some cases where any of these may have to occur for the purposes of scientific investigation, or to preserve the species, permits must be issued by members of the Antarctic Treaty, and researchers must be sure to limit the activity to affect as few individuals as possible. Other protections in this protocol outline that non-native species cannot be introduced to the island, and that the balanced ecosystem cannot be disrupted. Furthermore, population assessments must be conducted on native species regularly enough to evaluate whether they are continuing to thrive. If they are not, then the problems facing the population must be addressed.

Adelie Penguins on an iceberg

Some of the most recent additions to the Environmental Protocol that have beneficial consequences for native penguins include: guidelines for reducing plastic pollution in Antarctica and the Southern Ocean (held in Prague in 2019), a non-native species manual (created in Santiago in 2016), identifying important bird areas in Antarctica (at a gathering in Sofia in 2015), meeting of experts on climate change (conducted in Baltimore in 2009), and many more in between those years, or before.

Setting an example

Thankfully, the Antarctic Treaty provides key protections to the native penguins of Antarctica, which include Gentoo, Chinstrap, Macaroni, Adelie and Emperor. It also sets a precedence across the world for many things: international cooperation for peace, appreciation for the importance of science, and respect for native wildlife. If it can be done there, then hopefully our leaders can use the Antarctic Treaty as a model, and transpose those practices (sometime in the near future) to the rest of the world when dealing with similar issues.

The Antarctic Treaty and Environmental Protocol have done so much to protect penguins. We look forward to seeing what happens in the future. Please help us continue to provide you this type of information by donating to Penguins International.

Read more about penguins in some of other blogs:

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References

“Antarctic Treaty Meetings.” Antarctic and Southern Ocean Coalition, www.asoc.org/advocacy/antarctic-governance/antarctic-treaty-meetings.

“Antarctic Treaty.” U.S. Department of State Archive, U.S. Department of State, 2001-2009.state.gov/g/oes/ocns/9570.htm#protocol.

“The Antarctic Treaty.” US National Science Foundation (NSF), www.nsf.gov/geo/opp/antarct/anttrty.jsp.

“Conservation of Antarctic Fauna and Flora.” Fauna and Flora | Antarctic Treaty, Secretariat of the Antarctic Treaty, 2019, www.ats.aq/e/faflo.html.

https://www.ats.aq/e/protocol.html#

https://www.ats.aq/e/antarctictreaty.html

Penguin ticks are well-adapted hitchhikers

ixodus tick

Penguin ticks are well-adapted hitchhikers

by Nataly H. Aranzamendi

Considering that some penguins live on remote islands, it is remarkable that ticks have managed to arrive to all seabird colonies around the world. Let’s discover tick strategies for survival and colonization.

Penguins are not immune to the presence of parasites. Similar to other marine birds living in colonies, we find penguins constantly infected by ticks. Ticks from the genus Ixodes are the most widespread ubiquitous parasite in marine bird colonies. 

As any other live organism, penguins are susceptible to parasite attacks.

Ticks have limited mobility and the only way for them to travel long distances is transported with the aid of their hosts. Ticks can quickly reproduce and spread on land in bird colonies, thanks to optimal conditions of bird agglomerations: Their proximity and interactions between individuals. Understanding parasite distribution, speed of spread, and possible impacts for bird health is a central topic in disease ecology. 

Transmission of parasites at terrestrial locations therefore is expected, but something that has puzzled scientists for a very long time is how those parasites can be found even in the most remote places, indicating that parasites might be able to survive oceanic conditions. After all, when penguins finish breeding or molting, they go back to the ocean for weeks or even months. 

However, many species of penguins reproduce on isolated islands or scattered colonies with low connectivity between them, potentially limiting the ability of ticks to disperse and colonize new environments, or at least that is what scientists have always assumed.

Ticks can even survive on penguins while in the ocean

In a recent set of experiments1, scientists have tested if ticks had the ability to survive and resist oceanic and physiological conditions imposed by penguins when traveling from one place to another. 

Ticks from the genus Ixodes were collected from a colony of Little Penguins in Australia. The survival of these parasites was tested in several experiments. First, ticks were exposed to experimental regimes of varying depths. In the past, scientists used to believe that these arthropods were not able to resist water pressure conditions at deep dives. However, in the experiments all ticks were able to survive and passed the test of 60 m in depth, which are the distances that Little Penguins can reach.

Penguins swimming in the ocean. Ticks can survive on them for weeks!

When ticks are buried deep within a penguin’s feathers, they have enough adaptations to survive even the harshest conditions

Then ticks were exposed to several temperature regimes. Arthropods can be very sensitive to temperature, which might affect their basal metabolism and their ability to survive. However, in the experiments most ticks survived to temperatures within the ranges experienced in a penguin’s body at sea. Depending on the tick’s initial body condition, some arthropods stayed alive even after two weeks, which is longer than the majority of Little Penguin trips. 

Subsequently, ticks were tested in a regime of saline conditions and once again they passed the test. These parasites also prefer certain locations in the penguin’s body, commonly found in the inner ear, the head and the upper body of penguins.

Penguins submerge underwater to dive for food, restricting the availability of oxygen for ticks. The group of scientists found that ticks had the capacity to close their spiracles (i.e. the organ that allows respiration) for periods that lasted longer than any penguin’s diving time.  The fact that penguins expose only their heads to breath after every immersion guarantees oxygen supply for the parasites found there, and could explain why the arthropods prefer certain body parts. 

In summary, penguin ticks have proved to be well armed to survive the harshest of conditions in terms of temperature, depth, salinity and starvation. Such characteristics might help facilitate the arthropod’s survival and dispersal, and their capacity to arrive at even the most remote islands. This would explain why scientists keep finding the same kind of parasites everywhere, even when islands are separated by thousands of kilometers.

These findings have answered a long-unconfirmed suspicion. The next step will be to understand the consequences that the presence of parasites have on individual penguin colonies and the risks for penguins when favorable conditions lead to increases in infestations. In the meantime, it is very likely that we will keep finding ticks attached to most traveling penguins. 

Did you know ticks attached to penguins (vs humans or pets, as we might commonly think). And that they could stay attached to the birds for so long? They are determined! Please let us know what you think. We also greatly appreciate any support you can give us by donating to Penguins International so we can continue to provide you this type of information.

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  1. Moon, K. L., Aitkenhead, I. J., Fraser, C. I., & Chown, S. L. (2019). Can a Terrestrial Ectoparasite Disperse with Its Marine Host? Physiological and Biochemical Zoology, 92(2), 163-176, doi: 10.1086/701726

Penguin Digestive Systems – Penguin preppers and their secret militia

King Penguin

Penguin Digestive Systems – Penguin preppers and their secret militia

by Emma Williams

Spending most of your life at sea creates a big problem for a penguin digestive system; what to do when you are on land, separated from your food source. Penguins have evolved an apparently simple solution. Penguins are hoarders. Extremely accomplished preppers, they carry their own personal larders with them. A penguin’s digestive system can become a perfectly adapted storage cupboard of undigested food. The food reserves are used sparingly when they come on land to moult and to breed.

The penguin digestive system allows them to build up large reserves of adipose tissue, protein and lipids

On closer inspection, the solution is not quite so simple. To get through often long periods of fasting, penguins build up large reserves of adipose tissue, protein and lipids. However, this ability is not sufficient on its own; they enlist the help of a secret militia without whom they could not survive: Gastrointestinal microbiota. Penguins are not alone in housing this army of helpers. Most animals, including ourselves, have co-evolved GI tracts teeming with useful microorganisms that play a vital role in digestion. In the “feast and famine” world of penguins, they seem to really have their work cut out.

The penguin digestive system is teeming with useful microorganisms that play a vital role in digestion

These mini ecosystems have been studied widely in mammals but have been largely neglected in penguins. This imbalance has now started to be addressed and a comparative study of GI microbiota in penguins1 has yielded some very interesting results. The researchers looked at the inhabitants of the GI tracts of four different species of penguin: King Penguin (Aptenodytes patagonicus), Gentoo Penguin (Pygoscelis papua), Macaroni Penguin (Eudyptes chrysolophus) and Little Penguin (Eudyptula minor). They studied the gut contents of wild birds by examining their faecal samples.

A healthy Chinstrap Penguin in Antarctica

Thirteen different phyla were found in the penguins. The two most dominant were Firmicutes, literally strong skin, a phylum that are active in carbohydrate metabolism, and Bacteroides, a group of anaerobic bacteria particularly helpful in converting sugars. Both microbiota are also commonly found in mammals. Actinobacteria and Proteobacteria, vital for gut homeostasis, were also found to be strongly represented in the penguins. Each of the four species of penguin studied were discovered to possess different microbial makeups in their digestive systems. The prize for most diverse microbial composition goes to the Macaroni Penguin followed by King Penguin, and Little Penguin with Gentoo Penguin being a valiant runner-up.

It is likely that diet, environment, and phylogenetic differences account for the variation in gut microorganisms. Another study that looked at the GI microbiota of Chinstrap Penguins (Pygoscelis antarctica)2 found that age played a part. There were significant differences between the internal communities of adults and those of chicks. Interestingly, these differences were also apparent between parents and their own offspring suggesting that environmental factors are more important than genetic factors in the chick microbiota.

As well as their vital role in nutrition and energy release, the GI army is also ready to fight inside the penguin digestive system. These micro-soldiers create a formidable force, a close-protection squad, shielding their host from marauding invaders: Pathogens. Bacteroides in particular benefit their host animal by preventing infection by potential pathogens that may colonize and infect the gut.

The complex community of microbiota defend against illness and disease. Little is known about this process in penguins. Indeed, researchers1 discovered many “unclassified” bacteria within penguin digestive systems. As yet we do not know the significance of these atypical army of residents, but they are likely to have some role in digestion as well as health and disease.

Worryingly, human pathogens have also been documented in the GI tracts of wild penguins1, including Campylobacter, Heliobacter and Streptococcus. The impact of these pathogens on the health of wild penguins is not yet known, although a human pathogen has been implicated in the death of a Little Blue Penguin in captivity3

Due to their tendency to live in dense colonies and to huddle closely together, penguins are particularly susceptible to pathogen transfer. The potential for catastrophic spread of disease is likely to be high.

Of course, if penguins are hosting significant numbers of human pathogens without ill-effects perhaps they might hold the key to human immunity.

What is clear is that penguins need their carefully evolved and sophisticated micro-militia within their digestive systems. They play a major role in the release of energy reserves, nutrition, metabolism and immunity. Disruption of these micro-ecosystems is likely to be disastrous to their hosts health and well-being. Knowledge and understanding of these complex inner communities and the relationship with their penguin hosts is still in its infancy. It is an exciting branch of study that just might provide new insights that lead to benefits for both humans and penguins. Long-live the penguin digestive system militia!

What amazing digestive systems penguins have. Please let us know what you learned by reading this blog. We enjoy bringing you this information. And we appreciate any type of support you can provide us, so please consider donating to Penguins International.

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  1. Dewar, M.L., Arnould, J.P.Y., Dann, P., Trathan, P., Groscolas, R., & Smith, S. (2013). Interspecific variations in the gastrointestinal microbiota in penguins. Microbiology Open, 2 (1), 195-204.
  2. Barbosa, A., Balague, V., Valera, F., Martinez, A., Benzal, J., Motas, M., Mira, A., & Pedro-Alio, C. (2016). Age-related differences in the gastrointestinal microbiota of chinstrap penguins (Pygoscelis antarctica). PloSone, https://doi.org/10.1371/journal.pone.0153215
  3. Boerner, L., Nevis, K.R., Hinckley, L.S., Weber, E.S., & Frasca, S. (2004). Erysipelothrix septicaemia in a little blue penguin (Eudyptula minor). Journal of Veterinary Diagnosis, 16, 145-149.

Why Don’t Penguins Fly?

Penguins swimming underwater

Why Don’t Penguins Fly?

by James Platt

Most of the world’s bird species have the capability of flight. In fact, of 11,000 known species of birds, there are only about 60 species including the Common Ostrich (Struthio camelus), Great Spotted Kiwi (Apteryx haastii) and 18 species of penguin that cannot fly at all, which is about 0.5% of all bird species. Why these different species evolved without flight could be due to several reasons; each one will have evolved to fit into a niche within its own environment.

Penguins were originally thought to have evolved separately from flightless birds, until quite recently when fossil records from New Zealand were discovered. These fossils revealed that they had likely descended from the order of Procellariiformes and its closest relatives including the Wandering Albatross (Diomedea exulans) and Antarctic Petrel (Thalassoica antarctica). This could be considered unexpected since the albatross is a bird that travels huge distances in the air. So why would a bird that has massive wings and uses them to glide across continents suddenly evolve into a flightless, chubby penguin?

An albatross flying through the air
Photo credit: Linda Martin

Why did penguins evolve to swim instead of fly?

To understand why they may have evolved in this way, first we must understand flight. Flight in birds is a tricky thing; it is a perfect balance between forces (lift, thrust, gravity and air resistance) that allow the bird to move through the air quickly and efficiently. Birds evolved hollow bones to allow them to be lighter and, therefore, lift off the ground much easier. They also have air sacs built into their body to keep a streamlined aerodynamic body shape that allows them to reduce air resistance. Birds need to stay light because the heavier they are, the more difficult it is to take off from the ground (Tobalske, 2007). In the case of some flightless birds like the ostrich, which weighs over 100kg, its wings would have to be huge to get it off the ground. Instead, they are incredibly fast runners. Similarly, with Emperor Penguins (Aptenodytes forsteri) that can weigh about 25kg, it would take large wings to fly and would not be very energy efficient. So they evolved to “fly” in the water instead. Now some penguin species have branched off and become much smaller and lighter than the Emperor Penguin, such as the Little Penguin (Eudyptula minor) at just 1.5kg, but by this time they were a fully distinct order of birds and had adapted to dominate the water.

An Emperor Penguin tobogganing on the snow
Photo credit: Mike Zupanc

It is believed that the Emperor Penguin is the oldest species of penguin and therefore was the first bird to try to dominate the ocean and land on the continent. But why in such a cold, harsh environment, and why would it become flightless? Well, it’s complicated and there could be many other reasons. There is a total lack of land predators which means they don’t have any immediate threats to fly away from. There is also an abundance of sea life to eat and a lack food resources on land, so they adapted to thrive off the oceans and then live on land, away from their biggest predator, the leopard seal (Hydrurga leptonyx). There are also many benefits to being flightless. Penguins have the opposite to most birds, they have incredibly dense bones that allow them to dive and swim better. Where most birds would have air sacs to stay aerodynamic, penguins can fill some of that extra space with a larger stomach and carry much more food for itself and its offspring — up to a 1/3 of its bodyweight. They can also dive much deeper than flying seabirds they may be in competition with and this allows them to make the most of what their environment has to offer (Alexander, 1999).

Part of the reason penguins swim is because flying is an energy-intensive activity

One more reason they may have lost the ability to fly is that flying is an extremely high energy activity and they need all the energy they can retain to stay warm (Elliott et al, 2013). Most birds use their energy for flying and the bird that is best at conserving its energy is the penguin’s closest relative, the Wandering Albatross. It uses wind to extend its glide times and allow it use as little energy as possible during its migration. It seems that this wasn’t energy efficient enough for some individuals and they evolved into penguins over the millennia as swimming is much more efficient because there aren’t as many forces to contend with (Culik and Wilson, 1991).

The evolution of the penguin and its loss of flight is far from a complete story and I suspect we will find out more in the coming decades as more fossils are uncovered. Leave your thoughts in the comments!

Isn’t it nice to learn why not all birds fly? Some of us might assume that just because something has wings they won’t always stay grounded.

We hope you enjoy learning this about penguins and we love bringing you this information. Please consider supporting Penguins International by donating to us today.

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King Penguins

References

Culik, B., Wilson, R. and Bannasch, R., 1994. Underwater swimming at low energetic cost by pygoscelid penguins. Journal of Experimental Biology197(1), pp.65-78.

Alexander, R. (1999). One price to run, swim or fly?. Nature, 397(6721), pp.651-652.

Culik, B. and Wilson, R. (1991). Energetics of under-water swimming in Adelie penguins (Pygoscelis adeliae). Journal of Comparative Physiology B, 161(3), pp.285-291.

Elliott, K., Ricklefs, R., Gaston, A., Hatch, S., Speakman, J. and Davoren, G. (2013). High flight costs, but low dive costs, in auks support the biomechanical hypothesis for flightlessness in penguins. Proceedings of the National Academy of Sciences, 110(23), pp.9380-9384.

Tobalske, B. (2019). Biomechanics of bird flight. Journal of experimental biology, [online] 210(18), pp.3135-3146. Available at: https://jeb.biologists.org/content/210/18/3135.short [Accessed 8 Jul. 2019].

What’s up with “Down”?

King Penguin with its chick showing penguin down feathers

What’s up with “Down”?

By Megan Spofford

Have you ever seen a young penguin that looks like it has completely different feathers than the rest of the members in its colony? Did you think, “What’s wrong with that one!?” Would you describe it as a “floof-ball”? If so, it would serve you to know that the floofiness factor comes from a special type of feather called “down” which is small, lightweight, and FLUFFY. For penguins, the down has a gray or brown coloration. In this article we will explore what makes this type of feather so special, and to show you that no, nothing is wrong with that penguin!

What are the types of down feathers in penguins?

In the grand scheme of down, you will find there are three different types. Regular body down is a layer of lighter feathers found situated underneath and around the external contour ones that we see with our naked eye, and all birds possess it. Down feathers are classified as afterfeathers and plumules. Natal down is the first type of feather a baby bird will get, and it covers the entire body. Powder down is created from feathers that disintegrate into an ashy, powdery substance to coat the feathers of a bird in order to keep it waterproof from rain or any other type of wet substance it may encounter. This type of down is found on birds who typically do not spend time going into water, so a penguin does not have powder down. (Instead, penguins and other water birds have a uropygial gland, also known as a preen gland, at the base of their tail that secretes an oil which is spread over their feathers during preening. This oil serves to waterproof their feathers in the same way powder down does for other birds.)

What types of feathers does a baby penguin have when it hatches?

Altricial or Precocial?

Penguins hatch from an egg with down covering their body, however they are not able to feed on their own or survive if they were to leave the nest/ brood pouch. This characteristic makes them “semi-altricial”. An altricial bird is one that is not able to regulate the temperature of their own body, usually due to being completely or partially featherless. They are also heavily reliant on parental care for feeding. The latter is a particular reason why penguins are not considered precocial. While similar to precocial birds in that they are both born with feathering, a precocial baby will be able to fend for themselves or follow their parents around and to learn how to hunt within the first few weeks of life. On the other hand, as an altricial baby gets older, the down feathering thickens, and they are able to self-thermoregulate, but natal down is not waterproof, so until the penguin’s body is mostly covered in contour feathers that can be waterproofed, the bird cannot go into the water or it could risk drowning and hypothermia. Since penguins hunt in the ocean, the babies must rely on their parents for food until eventually, the young bird is old enough to molt (when a penguin sheds feathers on its body and is restored with new ones) and the down is replaced with adult feathers.

What are the additional purposes of down feathers in penguins?

Down has a few different purposes; a couple of which we have already described when discussing powder and natal down. Looking at the third type of down, body down, an important purpose it serves is as an insulating agent for any bird of any age. This is especially important to penguins who live in the cold Antarctic regions! Additionally, body down helps with a penguin’s movement in water. This help comes in the form of bubbles of air that are trapped in the down feathers and ultimately give the penguin buoyancy or allow it to zip through the water quickly. Sometimes in these high speed instances, a “trail of smoke” can be seen behind the penguin, which is really just the expulsion of those air bubbles from their down.

Close up of penguin feathers

Down feathers for Human Application

Recognizing the special properties of feathers, humans have started research into creating a diving suit made of artificial feathers that would be more insulating and create less drag during underwater excursions. The fluffier down feather would be an important feature for both of those properties to exist. If this ever comes to fruition, we would be the silliest looking penguin there ever was!

Did you know you could get ‘down’ with penguins? Great info! Let us know what you think. And please help us continue to bring you this type of info by contributing to Penguins International.

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References:

  1. https://web.stanford.edu/group/stanfordbirds/text/essays/Precocial_and_Altricial.html 
  2. https://www.beautyofbirds.com/birdoilgland.html 
  3. http://www.paulnoll.com/Oregon/Birds/feather-down.html 
  4. Jan R. E. Taylor, Thermal Insulation of the Down and Feathers of Pygoscelid Penguin Chicks and the Unique Properties of Penguin Feathers, The Auk, Volume 103, Issue 1, January 1986, Pages 160–168, https://doi.org/10.1093/auk/103.1.160
  5. Starck, Johannes Matthias. Avian Growth and Development: Evolution within the Altricial-Precocial Spectrum. Oxford Univ. Press, 1998, books.google.com/books?id=A0HB7Mq4lOYC&printsec=frontcover#v=onepage&q&f=false.
  6. Williams, CL, Hagelin, JC, & Kooyman, GL. (2015). Hidden keys to survival: The type, density, pattern and functional role of emperor penguin body feathers. Proceedings of the Royal Society B: Biological Sciences, 282(1817). http://dx.doi.org/10.1098/rspb.2015.2033 Retrieved from https://escholarship.org/uc/item/0xs4w8d0 

Penguin Fight Club

Humboldt Penguins fighting

Penguin Fight Club

By Martin Franklin

As readers of a certain age will know, both the first and second rules of Penguin Fight Club are, “You do not talk about Penguin Fight Club.” 

That, however, would mean an especially short and (even more than normal) disappointing blog post. 

I’m therefore going to bend the rules this once, not least as penguin combatants themselves often discard the rules of Fight Club, in particular, as Brad Pitt’s character so clearly articulates, “Fourth rule: Only two guys to a fight. Fifth rule: One fight at a time, fellas.”

Numerous members of the colony at ZSL London Zoo involved in a brief squabble  (© Martin Franklin/ZSL)

Fictional penguins tend to bend the rules even further. For example, Batman’s old adversary “The Penguin” used technology to fight, frequently using modified high-tech umbrellas as weapons. Similarly, the clay-animated “Feathers McGraw” disguised himself as a chicken by pulling a rubber glove over his head, used robotic “Techno Trousers” to steal a diamond, and trapped Wallace and Gromit in a wardrobe at gunpoint. 

Real penguins do, however, thankfully tend to stick to a fairly well documented and more traditional set of agonistic behaviours (i.e. social behaviours related to fighting)1, 2, 3. These include:

.

1. Visual penguin displays from a short distance 

  • Staring. This may be a “sideways” stare (where the head is held to one side, with one eye fixed on the opponent), or “alternate staring” (where the head is moved from side to side, and opponent stared at with each eye alternately). The whites of the eyes may be exposed. 
  • Pointing. The bird points its closed bill directly towards the opponent (sometimes with neck-rotation). This is often used by birds on nests towards other birds that venture too close.
  • Gaping. The bird leans towards its opponent, with neck stretched and bill open.
Humboldt Penguin pointing, while standing (© Martin Franklin/ZSL)
Humboldt Penguin posturing (© Martin Franklin/ZSL)
Humboldt Penguin pointing, while incubating (and guarding) eggs (© Martin Franklin/ZSL)

2. Penguin Vocalisations (combined with visual displays)

  • Ecstatic displays (also called trumpeting). This can either be performed by an individual or in pairs (in which latter case it is termed a “mutual” ecstatic display). It involves stretching the neck upward and flippers outward, and making one or more loud donkey-like brays (potentially also rolling the head from side to side, depending on the species). Context, however, is everything, as although such displays often indicate ownership of (or claims to) territory (particularly nest sites), and are often seen in connection with fights, they can also be used to advertise availability for mating and communicate identity (e.g. to a partner elsewhere on the beach). 
  • Growling/hissing. This is produced during exhalation and may accompany, for example, “pointing” (particularly in the crested penguins) or “lunging” (particularly in Little Penguins).
Humboldt Penguin ecstatic display (single bird) (© Martin Franklin/ZSL)
Humboldt Penguins mutual ecstatic display (1) (© Martin Franklin/ZSL)
Humboldt Penguins mutual ecstatic display (2) (© Martin Franklin/ZSL)

3. Physical/Close Contact

  • Charging/lunging. The bird runs or lunges towards its opponent.
  • Pecking. The closed bill is used to make a hard, speedy jab (often following “pointing”).
  • Bill vibrating. Two birds rapidly and repeatedly clap their bill against the other’s bill (think of “fencing”).
  • Biting. A pinching grip (particularly on the opponent’s neck or back), making use of the sharp hook on the end of the bill (which is otherwise primarily useful for grasping fish), sometimes in conjunction with pulling and twisting.
  • Beaking (also called the tête-à-tête posture). Two birds interlock their bills, then pull and twist to try to dislodge the opponent.
  • Beating. During “biting”/”beaking”, the bird rapidly and repeatedly slaps its opponent with a flipper. (The author can attest that this is surprisingly painful when a bird elects to perform this on a human.)

Of course, differences are observed in different species. 

 

For example, Adélie Penguins seem also to use a “bill-to-axilla” threat posture3 (which looks a bit like they’re trying to smell their armpits). Incidentally, it has been suggested that, just like in the worst human soap-operas, the most aggressive fights between Adélie Penguins occur when a female returns to her nest after an extended absence, only to find another female has pair-bonded with her former mate4.

 

Little Penguins (in which it seems around 10% of aggressive interactions escalate to fighting) similarly possess a significant repertoire of distinct agonistic behaviours (22 in cave-nesting birds and 13 in burrow-nesting birds). Some of these actions are common to most penguins, as already described above. Others (as far as the author is aware) are yet to be widely reported upon in relation to other species. These include the “zig-zag approach”, the “breast butt” (think of an angry soccer player with his arms held rigidly by his sides squaring up to another) and a variety of nuanced flipper-spreads.5

 

So what should the reader do, should he/she find him/herself on the wrong end of any such agonistic penguin behaviour? 

The author suggests (without any guarantees) that a generally sensible course of action might be to attempt the kind of “appeasement” or “displacement” behaviour deployed by penguins.  

 

Therefore, increasing the distance between you and your aggressor is probably the best tactic. However (and the following is not meant seriously):

  • If stationary, try the “submissive hunch”, the “face-away”, or “look-around” (rotate your retracted neck), or start “preening” yourself (good luck with that one). 
  • If walking through a colony, try “slender-walking” (with body stretched up, neck extended, flippers very slightly spread, and – if you can manage it – feathers sleeked down). 
  • Alternatively, get yourself a warm coat and egg and join the male Emperor Penguins during breeding season: aggression is suppressed at this time, allowing them to huddle together for warmth3.

 

But please repeat nothing of this: after all, you know the first two rules of Penguin Fight Club.

 

© 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.

Wasn’t this a great read about penguin social behaviors and “Fight Club?” Let us know what you learned, and if you’re going to watch any movies this week.

And please help us continue to bring you more information about penguins by donating to Penguins International. We greatly appreciate your support.

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References

 

1 Merritt, K. and King, N. E. (1987). Behavioral Sex Differences and Activity Patterns of Captive Humboldt Penguins (Spheniscus humboldti). Zoo Biology, 6(2), 129-138.

 

2 Eggleton, P. and Siegfried, W. R. (1979). Displays of the Jackass Penguin. Ostrich, 50, 139-167.

 

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

 

4 De Roy, T., Jones, M. and Cornthwaite, J. (2013). Penguins: Their World, Their Ways. London: Bloomsbury Publishing.

 

5 Waas, J. R. (1990). ‘An Analysis of Communication during the Aggressive Interactions of Little Blue Penguins (Eudyptula minor)’. In David, L. S. and Darby, J. T. (eds). Penguin Biology. San Diego, California: Academic Press Inc. pp. 345-376.

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