Great Penguins
(Aptenodytes)
"Flightless Divers"

Emperor Penguins (Aptenodytes forsteri)

 


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Emperor Photo Gallery

The largest of all penguin species with a length of up to 48 inches and their weight ranges from 50 pounds when hatching to 100 pounds when the males arrive in late fall at the colony. They have a black head, chin, and throat with broad yellow ear patches on the sides of the head. The underside of the wings and belly are white, becoming pale yellow in the upper breast. Circumpolar, they are largely restricted to cold waters of the Antarctic Zone within the limits of pack ice, between 66 degree and 77 degree south latitudes. Main breeding areas are: Cape Washington - 20,000 to 25,000 pairs, Victoria Land - 21,700 pairs, Halley Bay - 14,300 to 31,400 pairs, and Atka Bay - 16,000 pairs. The Ross Sea sector contains ~80,000 pairs, over half the total population of the Emperor penguin. They are the only bird to remain in Antarctica permanently, breeding during the 5 month Antarctic winter on the sea ice in some of the coldest conditions on the planet. Recent (2004) satellite images from LIMA (Landsat Image Mosaic of Antarctica) have located 38 emperor penguin colonies. Of the 38 colonies, 10 are new, six have been repositioned and 6 colonies previously thought to exist were not found or disappeared. These six colonies were originally recorded north of 70 degree South, which suggests the emperor penguins maybe at risk from climate change. However in April 2012 British and American scientists reported that they had counted 595,000 emperor penguins in 46 colonies along the Antarctic coast. For the first time satellite imagery was used, surveying all of Antarctica and essentially doubling the previous number of emperor penguins in Antarctica. Since there was some concern that emperor penguins colonies might be lost because of changing environmental conditions, this data disproves this. There is now an accurate method of evaluating the numbers of emperor penguins. They eat fish and crustaceans, foraging up to 311 miles from their colonies. There are an estimated 200,000 pairs, and the population is stable. There is little human influence except in the Ross Sea sector where the breeding population has decreased in part due to human influence. There are no known subspecies. They do not build nests or defend a fixed territory, using their warm bodies to incubate and raise their chicks. Their colony is in an area that is in the lee of large icebergs to avoid the severe winds. They are social, and to stay warm themselves the adults rotate position in their compact huddle to make certain everyone gets a turn at being on the cold edge. They have 100 feathers covering one square inch, the highest feather density of any bird species. Like other penguins the Emperor has a thick layers of insulating feathers which are designed to keep them warm in water. Heat loss in water is much greater than in air. In addition to this, the Emperor has the largest body mass of all penguins, which further reduces relative surface area and heat loss. They are also able to control blood flow to their extremities, reducing the amount of blood that gets cold. They are able to recapture 80% of heat escaping in their breath through a complex nasal passage heat exchange mechanism. They have the longest molting period of all penguins lasting an average of 34 days. Unlike other penguins, they and the king penguin lay only one egg. Immediately after the egg is laid, the female leaves the nest for 3 months during the Antarctic winter, when the period of darkness may last more than 20 hours. The huddling male emperor penguins incubating eggs may spend most of a 24-hour period sleeping. The females can travel up to 70 miles back to the colony as the sea ice has doubled in size during the winter. The chicks are born a few days before the females arrive to the colony. Breeding success is around 60%. Emperor chicks may experience a 20% survival rate during the first year of life. Therefore 80% of the emperor population comprise adults 5 years and older. Great Southern Petrels are the main predators of chicks at some land colonies. The average life expectancy is 19.9 years. They can dive to a maximum of 1755 feet, remain maximally submerged for up to 22 minutes. Most dives are about 490 feet and the dives last 2 to 8 minutes. When the Emperor penguin swims through water, it is slowed, as all penguins are, by the friction between its body and the water, keeping its maximum speed between 6.7 mph to 8.9 mph. But for short bursts the penguin can double or triple its speed by releasing air from its feathers in the form of tiny bubbles. Roger Hughes a marine biologist from Bangor University and Paul Larsen(2012) found this phenomenon was possible because the Emperor penguin has a dense uniform coat of feathers. The bases of these feathers include tiny filaments, just 20 microns in diameter which trap air in a fine downy mesh and air is released as microbubbles so tiny that they form a lubricating coat on the feather surface. This reduces the density and viscosity of the water around the penguin, cutting the drag. Unlike other penguins they do not porpoise. The maximum walking speed is slow at 1.7 mph, they do not hop, but they do toboggan reaching speeds twice as fast as walking.

 


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Emperor Photo Gallery 1

Emperor Photo Gallery 2

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