Male Emperor Penguin and Their Ability to Go 4 Months Without Eating

Written by Florence Arès, Lina Bakaleinik, Laurane Lacroix, Chi Zhang

Ecological niche

The Latin name of the emperor penguin species is Aptenodytes forsteri (Butler). Lloyd S. Davis, who is a scientist in the matter of marine animals, explains that the emperor penguin has more in common physically with turtles than flying birds. In fact, like all animals that inhabit terrestrial surfaces, the emperor penguin is classified as a tetrapod. Due to its hunting and swimming abilities, which are not commonly seen in other birds, this species has a stronger link to turtles, because, like them, emperor penguins live both on land and in water. The main characteristic that differentiates the emperor penguin from other species of penguin is his abnormally large figure. In fact, he is the largest species of penguin that we know of (Vandermeer et al.). The emperor penguins do not need to fly to find their food because they can swim in the water. Other birds that fly do not store a lot of fat because that would weigh them down and so they would either require larger wings or be unable to fly at all. The extremely low temperature of Antarctica makes it necessary for the emperor penguin to store a lot of fat to keep its body warm. In fact, the emperor penguin’s large body harbours two layers of fat that facilitate their survival in the harshest conditions of Antarctica. It is essential to note that emperor penguins have notably small beaks and heads because the majority of their nutrients are allocated to fat storage, with a minimal portion dedicated to other parts of the body’s development (Vandermeer). Emperor penguins are like a substantial fat reservoir. Despite their relatively small height, averaging around 120 cm, they weigh approximately 40 kilograms. This suggests that these animals are primarily composed of fat (Vandermeer).

As specified by the Encyclopedia of ocean, these birds typically live in colonies, and they can be found along the coastline of Antarctica at a latitude of 36.7 (M). 28.4 (F) (Davis et al.). According to Emily Vandermeer from the World Wildlife Fund Canada, the emperor penguin can survive in Antarctica when the temperature of the environment drops to –50 °C. The speed of the cold wind in Antarctica can reach 200km/hour (Vandermeer). It is interesting to know that a NASA team discovered that in Antarctica, one-half of the year experiences continuous sunlight without sunset, while during the other half, the creatures live in darkness. In fact, the reason for this phenomenon is that as the Earth spins around its orbit, Antarctica is always a part of the planet that either remains in darkness or is in the spotlight due to its position. In the matter of emperor penguins, they spend most of their time near the ice pack, particularly when it forms a solid surface due to low temperatures. During the breeding and chick-rearing seasons, the colonies tend to stay on the ice shelves as it is a safer location (Vandermeer). Emperor Penguins have predators such as killer whales, which are often found near the pack ice where penguins swim to find their food, such as squid. In fact, cephalopods are the main food that nourishes many colonies of emperor penguins and are crucial for their diet (Zimmer et al.). However, the diet of the emperor penguin varies among different colonies due to differences in their geographical locations. The trophic position changes according to where the species is found. The emperor penguin plays an important role in the life of many species of squid (such as cephalopods), krill, and some species of fish, as well they are also important in the alimentation of leopard seals (Hirsh). As explained by Rebecca Hirsh, the diet of the emperor penguin consists of fish, squid, and krill that live around the coastline of Antarctica. While the emperor penguin is searching for food in the cold ocean of Antarctica, the leopard seals are also searching for food, but in this case, they are searching for the penguin because they compose their alimentation (Hirsh). Therefore, to not put in danger the life of the baby emperor penguin, which is unborn or unable to swim or run away from predators, the male of this species decides to stay with the younger generation, in order to protect them and raise them far away from the coastline of Antarctica.

Capacity that the species has and the advantage it confers

Male emperor penguins can fast for up to four months to protect their egg. From the moment, they bred to when the female penguins return with food for their chick months later, they fast. They can survive this long, by storing body fat and protein through the summer by eating extra nutrients. “During most of the incubation fast, birds rely almost entirely on lipids as an energy source, body proteins being spared,” according to René Groscolas in, “Long-term Fasting and Re-feeding In Penguins”. By doing so, they keep the stored protein as a survival guarantee if they lack lipids. This period of starvation is possible because they can store huge quantities of fat in their body. This type of penguin can lose 33-55% of their body weight (G. Dewasmes et al.), which is around half of their weight. During the incubation which is the period when male birds keep their egg warm, the female goes off to feed and bring back food for the chick. Once she is back, it’s the male turn to feed himself and forage. Always protecting the egg and constantly hatching gives it a better rate of survival. If it is left alone in the cold for too long there is a high risk that it would completely freeze to death. The male keeps the egg on his feet and warms it up with his feathers, skin, and fat. During this time, other males often snuggle together to keep the eggs warm since the temperature can reach -50 degrees Celsius. Also, exchanging the egg from one partner to another is extremely dangerous because there is a high chance of it being dropped and freezing before they can do anything. Only changing the egg from the female (after she laid it) to the male once, decreases the risks of it falling from their feet and increases the chances of survival of the chick. It is a huge advantage for this species since each couple only lays one egg a year.

Physical adaption

To survive the four months without eating while the emperor penguin’s chick broke the shell, the male emperor penguin uses a lot of physical adaptations such as metabolism. Metabolism is the process of multiple physical reactions like “absorption, degradation, transformation, excretion and utilization of nutrients supplied to the animal” (Wellion). During the four months, the emperor penguins’ metabolic rate changes due to their thermoregulation (inside body temperature changes) and locomotion (ability to move).

Their metabolic rate changes according to the temperature. When the temperature decreases, the rate of metabolism increases, when the temperature increases, the rate of metabolism decreases. For example, between 20 C° and -10 C°, the metabolic rate (standard metabolic rate (SMR)) is constant. At -47 C°, the metabolic rate is “70% above the SMR” (Pinshow et al.). Also, the metabolic rate increases when the speed of a motion increases. A high metabolic rate means that there is more burned energy at rest. The reason why the emperor penguins huddle together is because they need a low metabolic rate to slowly consume their energy during incubation (Qin and Buehler). Huddling is a very dynamic process, sometimes when the temperature of a penguin is too high (35 C°), it will go to the periphery or the outside of the group to cool down. The males reduce their metabolic rate to 75% of their resting metabolic rate while huddling during the four months of incubation (Kooyman and Wayne 23). The feathers are rigid, so the moderate-speed winds have little effect on heat loss (Le Maho, et al.) which leads to a lower metabolic rate.

Their metabolic rate also depends on exercise. For instance, when an emperor penguin is swimming, its metabolic rate is nine times bigger than a resting bird’s (22). The emperor penguins avoided moving during these four months for this reason, so they spent a lot of time huddling together.

The physical adaptations of the emperor penguins are the species that have the highest tolerance to cold. Knowing that emperor penguins are the largest penguins, their surface-area-to-body-mass ratio is the lowest, which reduces energy loss (62). Its feet are the only bare skin, but none of them touches the snow or ice while resting even with its egg on its feet. The feet are also tucked up under the feathers (62). This position of standing avoids potential heat loss. In fact, the temperature of their feet can be cooler than the body. It is called countercurrent circulation on the feet (64). The arterial blood goes to the penguins’ feet, and cold venous blood goes back to the body core, the heat transferred from arterial blood to venous blood. They have flippers to save heat and small bills relative to their entire size. A large portion of the heat that is often lost during exhalation is also recovered by their nasal chambers. The emperor penguins also have amazing “large reserves of energy-giving body fat” (Australian Antarctic Program).

Cognitive adaption

To ensure the survival of their egg, the male emperor penguin has the paternal instinct to go four months without food, during the period of the egg’s development. An instinct is “the natural behaviour and psychology of animals” (Craighead et al.). It can also be explained as the “species-typical or species-specific behaviours.” (Craighead et al.). As leaving the egg alone on the ice to hunt for food in the sea would put the egg at the mercy of the harsh weather, cold climates, and predators, the male emperor penguin has the parental instinct to stay with the egg to protect it. He also has the instinct to eat a lot before, during summer, to have reserves of energy during the period when he must protect the egg (Dewasmes et al.). The emperor penguin is instinctively able to know the time of the year thanks to the circadian clock. The “Circadian rhythms are daily (about 24 h) rhythms of behaviour, physiology, and biochemistry that are controlled by internal clocks. These rhythms are entrained by environmental and modulate cognitive performance” (Sitzberger et al.). For that reason, to this internal clock that dictates their behaviour, Emperor penguins instinctively know when it is time for them to feed themself in the prevision of the starving, and when it is time for them to starve to protect the egg.

Works Cited

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