Emperor Penguin—Distribution and Migration
|Emperor penguins with chick|
Emperor penguins (Aptenodytes forsteri), one of two called the great penguins (the other is the king penguin), live and breed in colonies distributed throughout the Antarctic continent, generally ranging from 67° to 77° south latitude. Although breeding takes place nowhere else, immatures are sometimes spotted on the eastern shores of the Falkland Islands in the South Atlantic Ocean. They always breed on stable fast ice (pack ice that is attached to land) and can be found up to 11 miles offshore. The rest of the year they stay within reach of the fast ice and pack ice of the continent and nearby waters.
Identifying Emperor Penguins—Physical Characteristics
Adult emperors have black heads with a black chin. Yellow tear-shapes, called auricular patches, are located on the sides of their necks and narrow down, as in a bottleneck, at the top of their shoulders. The yellow coloration then blends into a paler yellow at their chest on their otherwise white underside. They have a pink-orange band on a mostly black bill and their feet are black.
When they hatch the chick has gray skin and no feathers and is totally dependent on the adults for warmth. Their gray down fills in over the course of a few weeks with a black crown that extends from their bill to the back of their head and the sides of their neck, with white cheeks and chin. As the chick grows, the black pattern extends to their entire back. When immature, emperors are gray-blue while the adults are black, and their auricular patches as well as their undersides are white. Their bills are black with little white.
As the largest penguins now living, the adults are 40–52 inches in height, taller than most people’s waistlines. It is important to understand that these birds do not eat three meals a day and their metabolisms compensate by allowing them to lose tremendous amounts of weight during the harsh breeding season with no overall harm to most successful breeders. A male can start the breeding season at 83 pounds and end it at a little over 50 pounds—120 days after the breeding season begins when they first get to forage again. Females, considerably smaller to begin with at around 63 pounds, drop 22% of their weight during breeding to 50 pounds.
Emperor Penguin Habitat
|Emperor penguins feeding chick|
The most successful colonies are those that are on stable pack ice in bays between islands that are somewhat sheltered from the biting winter winds by icebergs. However, there are other cases that are successful, such as the emperor colony by Taylor Glacier in Kemp Land in east Antarctica that is situated in a cirque, the concave mountaintop leftover of an ice cap.
Emperor Penguin Diet
The first food of the emperor chick is a milky substance, full of protein and fats, secreted by the male’s esophagus after almost four months of fasting. Shortly thereafter, if all goes well, the chick will be nourished with food from the female when she returns from her foraging outing—which she began shortly after depositing her egg on the feet of the male.
As with other penguin species, their diet varies depending on the availability of prey. They pursue krill (a shrimp-like crustacean), cephalopods (particularly squid) and fish in dives that can last up to 20 minutes and generally extend down over 150 feet. They have been recorded, rarely, diving down to over 800 feet and, at least once, to over 1,600 feet.
Emperor Penguin Behavior
A mutual display whereby they bow their heads to one another is the accepted form of recognition when they return from feeding expeditions.
Movement across vast ice expanses is often helped by the rich fat reserves on their bellies as they flop down and push themselves along the ice with their feet. This tobogganing behavior is only used by one other penguin species, one that also exclusively breeds on the Antarctic continent, the Adélie penguin.
Emperor Penguin Breeding and Mating
During the months of March and April (autumn in the southern hemisphere) emperors three years of age and older march—often one behind the next—across pack ice to get to the location of their natal breeding colony (the colony of their birth). They do this at speeds approaching one mile per hour and alternate between walking—or, more accurately, waddling—and tobogganing as described above. Once at the colony they exchange breeding calls and displays. Interestingly, they raise their flippers, rub their bill beneath their flipper and trumpet, displaying their neck patches prominently—but not if there’s another bird doing the same within a 23-foot radius. So even though they do not construct nests and, therefore, do not defend a nest territory, they do control a personal space for attracting mates. Once they have selected a mate, the male waddles behind the female as they strut through the colony. They then turn, bow to one another and mate. The egg, once laid, is immediately transferred to the feet of the male.
|Emperor penguins tobagganing into water|
Incubation of the greenish-white egg extends from 62 to 67 days and is accomplished in great groups of huddling males, while the females march back to the water’s edge to feed—and time their return to coincide with the hatching of the chick. The males can lose up to 50% of their body mass during this parental fast and, only after the females return to a hatched chick, return to the sea themselves to forage.
The chicks fledge when they are about five months old and are abandoned by the adults before their first adult feathers, but this is timed for when the edge of the sea ice is closest to the colony to minimize the time of their first march to sea.
Emperor penguin chicks must endure the harshest winter on Earth to survive their first year. But, unlike for other penguin chicks, predation is nonexistent when they are at their most vulnerable—they are pretty much the only living beasts on the continent at that time of year.
Emperor Penguin Social Behavior
Emperor penguins are highly social, living and feeding in large groups. Although they remain with one mate during the breeding season, they rarely pair with the same mate again the following season.