Emperor penguin (Aptenodytes forsteri) | Polarjournal

Height: up to 105 cm – Weight: 30 – 40 kg – Life expectancy: up to 20 years

Habitat

The emperor penguin lives and breeds exclusively on the edge of Antarctica between the 66. and 78. latitudes. During their “oceanic phase”, emperor penguins migrate to the area of the pack ice belt. When fishing, they can dive under the ice down to 500 meters and stay underwater for more than a quarter of an hour.

The chicks hatch, after about 64 days of breeding, from mid-July and have time until January to fledge. The belly fold of the parents offers security to the chicks in their first months and, above all, protection from the bitter cold.

Breeding behaviour

Emperor penguins start breeding between the ages of 3 and 6. It is one of the most unusual curiosities of nature that the emperor penguins not only breed in the coldest area of the earth, but also do so in winter instead of summer. At the beginning of April, the emperor penguins migrate inland, after they have fed themselves under the pack ice. Now the mating season begins, and in May/June, in the middle of the Antarctic winter, they start breeding.

The emperor penguin female lays only one white egg, which weighs about 450 grams. After the laying the egg, the female hands over her egg to the male. The females now leave the colony and return to the sea to put on fat for the turnover during breeding and gather the first proper meal for the chick. Long distances are usually covered by sliding on their belly. The distance to the ice edge can be up to several hundred kilometers at this time.

Sledging: In order to save energy on the long way to the sea, emperor penguins slide on their belly over the ice.

While the females forage, the males hatch the egg in their warm breeding pouch. A colony of breeding males can range between a few dozen to a few thousand animals. Because the emperor penguin males do not feed during the two-month breeding phase, they lose up to half their body weight during this time. In order to keep warm, the animals in the colony gather close together and change their position regularly, so that each animal stands at the edge and sometimes in the warmer interior of the colony. This happens during the polar nights, which are brightened at most by some aurora. The temperature ranges from minus 60 to minus 70 degrees and at times, furious snowstorms sweep across the ice.

To protect themselves from cold and storms, the emperor penguins form colonies. In the event of impending storms, they stand close together.

After 64 days, the chick hatches and is fed by the father for the time being with a crop secretion. Now finally, the female returns, after having traversed the long distance “land road” again. The well-fed mother, who carries about 3 kilograms of pre-digested fish in her stomach, can feed the chick for two to three weeks. The father, meanwhile, marches with all the other emaciated males to the sea to dive under the pack ice for food.

The parents bring about three kilograms of pre-digested fish from their trips to the sea back to their chicks. The fish is ‘intermediately stored’ in the crop.

Now the time for joint feeding begins. While one parent hunts, the other is busy feeding the chick. On average, each parent animal migrates eight times to the sea and back again, so that the chick is fed 16 times. Feeding takes place in several stages, spread over two to three days. At the age of five to seven weeks, the chicks begin to gather in the so-called crèches. All chicks stand close together to protect themselves from the cold and storm. Due to the long way of the parents to the sea and back, the chicks always have three to four food-free days.

Family happiness with the emperor penguins. The stock is considered stable. The number of sexually mature and thus reproductive emperor penguins has so far been estimated at 270,000 to 350,000 individuals. Recently, according to satellite images, a number of 595,000 animals in 46 colonies is expected.

Selfsustaining foraging

As expensive as it is to provide food for the parents, it brings a decisive advantage for the chicks: in November, at the start of the Antarctic summer, the hunger of the chicks far exceeds the amount of fish that the parents can bring. But thanks to the sun, the ice has broken up over long distances, so the way to the sea is not far. For the parents, the distance over the ice is getting shorter and shorter.

When summer starts, the young emperors finish their molting phase and leave the colony to begin their wandering years. Three to six years later, they will return to their birthplace and breed for the first time.

The emperor penguins manage to breed with this rhythm every year. Their closest relatives, the king penguins have only two breeding phases in three years.

A storm arose, the penguins stand close together. The thermometer showed -32 degrees Cel. and the wind gusts were over 100 km/h. In the picture ice crystals are visible that got lost inside the camera and were exposed.

Energy-saving world champion

The penguins have a thick layer of fat in their subcutaneous part of the skin, the blubber, which reduces heat loss to a minimum. When they breed during the Antarctic winter, stormy winds will drop temperatures to minus 60 degrees. But within their body, the penguins can maintain plus 39 degrees Celsius. The temperature difference between inside and outside is therefore a whopping 100 degrees Celsius. Emperor penguins are true energy-saving world champions!

Heiner Kubny, PolarJournal (text + images)

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