Emperor Penguin Aptenodytes forsteri

The Emperor Penguin Aptenodytes forsteri is found throughout Antarctica within the limits of pack ice. Emperor Penguins walk right up to the human visitor and trumpet their arrival. Their calls are used to recognize each other and form pairs for mating. An estimated 400,000 - 450,000 individual Emperor Penguins with 195,400 breeding pairs populate Antarctica; the Ross Sea area has half the total population of Emperor Penguins.


Emperor Penguins mainly eat nototheniid fish, squid, and euphausid and amphipod crustaceans which they pursue to capture, diving down to 500 meters for a usual duration of twelve minutes. Emperor Penguins can dive to almost 600 meters and stay underwater for twenty minutes on a shallow dive. Emperor Penguins swim 2.4 - 3.4 meters per second during foraging (5.4 - 7.6 miles per hour) and have been measured at maximum speeds of 4.6 - 7.1 meters per second (10.3 - 15.9 miles per hour). A single foraging trip may involve travel up to 150 - 1,000 kilometers with travel speeds ranging from 1.5 - 2.5 kilometers per hour.

Emperor Penguins breed on level, stable sea ice with only two colonies known on land. This picture was taken at Cape Washington which has a large breeding population of 20 - 25,000 pairs. Before breeding, males weigh more than females ranging from 35 - 40 kilograms and 28 - 32 kilograms respectively. Emperor Penguins return to their breeding colonies in March through early April, oftentimes walking 50 - 120 kilometers over sea ice to get there. A single, large egg is laid in May through early June. Emperor Penguin egg laying, incubation, and chick rearing takes place in the Antarctic winter; other penguin species do this in the Antarctic summer. Emperor Penguins are very colonial, are not territorial, and are monogamous within that breeding season (but only 15% of the mating pairs retain the same partner the following year). Male Emperor Penguins are responsible for egg incubation and they huddle closely in large groups for warmth during the two months of egg incubation. During their breeding fast, Emperor Penguin weight decreases by 35 - 40% in males and 20 - 25% in females; the males lose more weight since they incubate the egg. After egg hatching, both parents alternate chick brooding for its fifty day period; one goes off to feed while the other. Chicks then form large creches until they depart from the colony in December through early January. When left alone while its parents are out feeding, the Emperor Penguin chick regularly calls for its parents who use that call to locate their chick.

Penguins were first discovered in 1520 during Magellan's circumnavigation; the expedition historian, Pigafetta, called them "strange geese"; the Emperor Penguin was described in 1844 from the expedition of Sir James Clark Ross.

Review: The Penguins, Spheniscidae. TD Williams. Oxford : Oxford University Press, 1995. pp.152-160; Diving Physiology: American Scientist 85: 530-539, 1997; Swimming Speed: Journal of Experimental Biology 165:161-180, 1992

Text ©Peter Brueggeman. Photographs ©Norbert Wu. Photographs may not be used in any form without the express written permission of Norbert Wu. Norbert Wu no longer grants permission for uncompensated use of his photos under any circumstances whatsoever; want more info?