Photo of King Penguin. Photo credit: saname777 [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], from Wikimedia Commons
Fish Beware! – Penguins Adapt Effective Means of Capturing Prey
By Mike King
Scientists currently split the penguin family into 18 different species that occur all over the Southern Hemisphere. As these penguin species evolved from a common ancestor, they each gained unique traits. One of the most important traits that penguins have adapted is how they eat. Most people know that penguins swim underwater and catch marine prey instead of flying like other birds, but there is actually a lot of variation in the specific feeding behaviors exhibited between separate penguin species. From krill to fish, sea to shore, and even day to night; there is a lot to learn about how different penguins keep themselves, and their chicks, happy and healthy.
Scientists are not sure how long ago penguins lost the ability to fly, but it’s thought that as the birds’ wings became more adapted for swimming, they lost the lengthy surface area of feathers needed to hold the birds aloft. It is more difficult for flightless birds to escape from predators like leopard seals; but the reward is well worth the risk. Since the wings of the penguins have evolved into streamlined flippers, they are able to swim with incredible grace and agility through great depths of water in search of food. Emperor Penguins (Aptenodytes forsteri) can routinely dive well over 200 meters while holding their breath for up to 20 minutes! This can be very helpful for catching Antarctic Silverfish, which spends most of its time between 200 and 300 meters below the surface. This is just one example of how penguins evolved alongside their food source, enabling them to keep up with their prey as the fish began to swim deeper and faster.
How do penguins find food?
While Emperor Penguins spend their time diving to great depths in search of fish, other penguin species have their own methods for finding food. Gentoo Penguins (Pygoscelis papua) are extremely fast swimmers, although it’s important to note that reports of top speeds on various websites of 22 miles per hour are unsubstantiated and their top speed is currently unknown. Galapagos Penguins (Spheniscus mendiculus) utilize a technique where they dive beneath schools of fish, then swim upwards and drive the fish toward the surface. This traps the fish between the penguins and other species of seabirds at the surface that cannot dive so they have nowhere to escape. Many species, like Little Penguins (Eudyptula minor) stay in the water all day to find enough fish to feed themselves and their offspring.
Penguins almost always live in close proximity to other vertebrate species. Whether it’s seals, fish, or even other penguins, there is bound to be some competition for food. This is why penguins have evolved many ways to fill their own ecological “niche.” A niche is an organism’s place in the ecosystem, where most of the resources they need to survive are readily available to them. Ecological niches help animals ensure the survival of their own species by avoiding harmful interactions with other species. A good example of this is Gentoo and Emperor penguins. While both species live and hunt in Antarctica, they do not compete for resources. Emperor Penguins make deep dives in search of fish, while Gentoo Penguins speedily cruise near the surface of the water in search of krill. This division of foraging techniques is the line between the ecological niches of the two species.
Sometimes, when resources are scarce, animals must adapt new techniques to continue providing enough food for themselves and their offspring. Until just this year, scientists believed that male Emperor Penguins fasted for 115 days while they incubate their eggs. This would be a monumental task for these birds who, like all organisms, need energy to metabolize and survive. If an adult Emperor Penguin dies of starvation while incubating, his offspring also would not survive. A recent research article written by Gerald L. Kooyman et. al. in January 2018 may shed some light on how Emperor Penguins survive this long period of incubation. There is a colony of penguins near the Ross Sea in Antarctica that is one of the strongest of all Antarctic populations. A team of researchers set out to examine why, at a latitude much farther south than most other Emperor Penguins, this group was faring so well. It turns out, the males in this colony do not participate in the 115-day annual fast. In the dead of winter, when days are very short, these penguin males relinquish their parental duties to the females for one night; to dive for fish–in the dark. Prey becomes harder to see at night, as do predators. These Emperor Penguins, however, have taken advantage of the underutilized populations of fish found in the Ross Sea after dark. This adaptive trait has allowed their population to become one of the most stable of any penguin species in the world.
Photo credit: https://nauticallog.blogspot.com/2010/12/ross-sea-whaling.html
Penguins have to constantly adapt to survive, however.
Much like penguins developing different foraging behaviors, animals are constantly adapting to the challenges presented to them by nature. As problems arise, organisms must find ways to overcome them. This incredible race for survival drives all living things to further evolutionary advancement, and results in the splendid array of biodiversity we know in our world today. However, for the first time ever, one species has advanced itself so greatly that it threatens to irreversibly tip the balance of nature toward destruction. Because of climate change, illegal hunting and fishing, and over-exploitation of natural resources, humans are at risk of causing the largest mass extinction in the history of the world. Although animals, like the Emperor penguins of the Ross Sea, are capable of rising above challenges presented by nature, it can be difficult or impossible for them to evolve quickly enough to face challenges brought on by human industry. In order to halt this catastrophic extinction event that has already begun, immediate action is needed. Legislation must be passed to protect natural habitats, awareness must be raised for issues affecting wildlife around the world, and small changes must be made in each of our lives to benefit the Earth instead of exploiting it. It is up to humans to help the ecosystem return to its natural state, for the benefit of ourselves and all other organisms that call the Earth home.