Of the seventeen species of penguin in existence, the emperor penguin is arguably the most well-known and heavily documented. Depicted in films such as March of the Penguins and Happy Feet, it is difficult not to be endeared by the flightless birds and their fluffy chicks, so it is no surprise that they have been documented once more in BBC’s Dynasties.
In the second post of our Dynasties blog series, we’ll be exploring how emperor penguins and their flippered relatives interact with each other to build their respective dynasties in the chilly Antarctic.
- Who’s the tallest of them all?
Standing over a metre tall, the emperor penguin is the tallest penguin of all the species alive today. However, it is not the tallest penguin there has ever been on this planet. Over the years, several fossilised ancestors of penguins have been identified, the oldest of which is around 60 million years old. A recent study suggested that this penguin ancestor would have been 5 foot, 7 inches tall – taller than the average human woman!
- Frosty incubators
Like most members of the animal kingdom, penguins breed during the spring and summer – except emperor penguins. Instead, emperors brave the bitter winters of the Antarctic to lay their eggs, incubating until they hatch in the spring, and raise their chicks in the summer. Through this method, the penguins avoid exposing their chicks to the frosty climate as much as possible, allowing them to mature before the next winter hits.
- Chick-rearing vs. hunting
The closest relatives to emperor penguins are the king penguins, who look very similar as adults but whose chicks are significantly different in appearance. King penguins vary in hunting behaviour at different stages of the chick-rearing cycle depending on their age and breeding experience. For example, during the incubation stage, younger breeders take longer hunting trips, while more experienced breeding penguins take shorter foraging trips during the early stages of the chick’s life. Furthermore, females have been found to spend less time hunting than males.
- Krill or be krilled
Antarctic penguins, including the Emperor penguin, are dependent on krill for food. In particular, young penguins – who are constantly growing until they become an adult – rely on krill to survive; if the number of krill is particularly low at any point, juvenile mortality increases. Penguins compete for krill against other predators, including leopard seals, who also hunt penguins! Many seabirds, including penguins, have also been known to ingest plastic debris, which can lead to obstruction of the gut and poisoning through the toxic chemicals found in plastic, eventually leading to death. This issue was explored in the memorable episode of Blue Planet II narrated by Sir David Attenborough, and our accompanying blog post: ‘Our Blue Planet’.
- Hunt and be hunted
As penguins are in the middle of the food chain – hunters of krill but hunted by seals – diving into the sea is risky but necessary for all species of penguin in the Antarctic. Adelie penguins have developed a behaviour which favours the many: the colony observes their fellow penguins before deciding whether to dive in or not, waiting for the bravest/hungriest penguin to take the plunge. The colony will then only follow the first penguin into the water if the water is proven safe, i.e. they aren’t attacked by a seal upon entering the ocean. Although this strategy is unfair on the bravest penguin, which has a good chance of dying when they hit the water, it does prevent a massacre of the colony should there be any seals waiting in the water.
- Equal partnerships
The chick-rearing habits of emperor penguins are widely known: the female will lay the egg to be incubated by the male, while the female travels to the ocean to hunt; when she returns a couple of months later, the females regurgitate the fish they ate to feed their new-born chick, while the males take their turn to go hunting in the ocean; the pair will then continue to switch between hunting and chick-rearing for the early months of their offspring’s life. In contrast to this equal partnership, in over 70% of cases little penguins choose to exercise unequal parenting effort, despite the fact that being an equal pair is a more effective strategy, suggesting quality of character plays a role in how dedicated little penguins are as parents.
- Love isn’t black and white
Did you know that penguins were the first species observed to have same-sex pairings? Between 1915 and 1930, Edinburgh Zoo kept a group of penguins, which were named according to their assumed male/female pairings. However, after several years and various observations, the zoo realised that they had got many of the penguins’ genders wrong, finding male and female same-sex couples to be present in addition to the heterosexual couples! Since then, many homosexual pairs have been observed in nature and in zoos, including Roy and Silo at Central Park Zoo in New York, who famously hatched and raised an orphaned chick and have since been the subject of children’s picture book And Tango Makes Three.
Featured image credit: Emperor penguins by Christopher Michel. CC BY 2.0 via Flickr.