Emperor penguin: Difference between revisions
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===Reproduction=== |
===Reproduction=== |
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[[Image:PENGUIN LIFECYCLE H.JPG|left|thumb|The life-cycle of the Emperor Penguin]] |
[[Image:PENGUIN LIFECYCLE H.JPG|left|thumb|The life-cycle of the Emperor Penguin]] |
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Emperor Penguins first begin to breed at approximately five years of age. Emperor penguins travel about 90 km (56 mi) inland to reach the breeding site. The penguins start courtship in March or April, when the [[temperature]] can be as low as –40°C. Emperor Penguins are [[Serial monogamy|serially monogamous]]. They have only one mate each year, and stay faithful to that mate. However, the next year, most end up with different mates. Although they attempt to locate the previous year's mate in the next breeding season, most cannot find each other and choose a new mate. |
Emperor Penguins first begin to breed at approximately five years of age. Emperor penguins travel about 90 km (56 mi) inland to reach the breeding site. The penguins start courtship in March or April, when the [[temperature]] can be as low as –40°C. Emperor Penguins are [[Serial monogamy|serially monogamous]]. They have only one mate each year, and stay faithful to that mate. However, the next year, most end up with different mates. Although they attempt to locate the previous year's mate in the next breeding season, most cannot find each other and choose a new mate.dum dum |
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In May or June, the female penguin lays one 450 [[gram]] (1 lb) [[Egg (biology)|egg]], but at this point her nutritional reserves are exhausted and she must immediately return to the sea to feed. Very carefully, she transfers the egg to the male, who [[incubate (bird)|incubates]] the egg in his brood pouch for about 65 days consecutively without food by surviving on his fat reserves and spending the majority of the time sleeping to conserve energy. The transfer of the egg can be awkward and difficult, and many couples drop the egg in the process. When this happens, the chick inside is immediately lost as the egg cannot withstand the low temperatures on the icy ground. To survive the cold and winds of up to 200 km/h (120 mph), the males huddle together, taking turns in the middle of the huddle. They have also been observed with their backs to the wind to conserve body heat. If the chick hatches before the mother's return, the father sets the chick on his feet and covers it with his pouch, feeding it a white, milky substance produced by a gland in his esophagus. |
In May or June, the female penguin lays one 450 [[gram]] (1 lb) [[Egg (biology)|egg]], but at this point her nutritional reserves are exhausted and she must immediately return to the sea to feed. Very carefully, she transfers the egg to the male, who [[incubate (bird)|incubates]] the egg in his brood pouch for about 65 days consecutively without food by surviving on his fat reserves and spending the majority of the time sleeping to conserve energy. The transfer of the egg can be awkward and difficult, and many couples drop the egg in the process. When this happens, the chick inside is immediately lost as the egg cannot withstand the low temperatures on the icy ground. To survive the cold and winds of up to 200 km/h (120 mph), the males huddle together, taking turns in the middle of the huddle. They have also been observed with their backs to the wind to conserve body heat. If the chick hatches before the mother's return, the father sets the chick on his feet and covers it with his pouch, feeding it a white, milky substance produced by a gland in his esophagus. |
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Revision as of 18:37, 21 February 2008
 | This article needs additional citations for verification. (December 2007) |
| Emperor Penguin | |
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| Scientific classification | |
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| Species: | A. forsteri
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| Binomial name | |
| Aptenodytes forsteri | |
The Emperor Penguin (Aptenodytes forsteri) is the tallest and heaviest of all living penguin species. It is endemic to Antarctica, and is the only penguin species that breeds during the Antarctic winter. Emperor Penguins mainly eat fish but also take crustaceans (such as krill) and squid. Emperor Penguins typically live for 20 years in the wild, but some records indicate a maximum lifespan of around 40 years. The Emperor Penguin should not be confused with the closely related King Penguin or the Royal Penguin.
Description
The adult Emperor Penguin stands up to about 120 cm (47 in) tall and can weigh anywhere from 22 to 37 kg, depending on where it is in the reproductive cycle, because both male and female penguins lose substantial portions of their mass while raising hatchlings and incubating eggs.[2] The adult has deep black feathers dorsally, including the head, chin, throat, back, dorsal part of the flippers, and tail. These dark feathers fade to a brownish color as they become worn, usually between December and February.[2] The belly is white from the upper breast to venter and the underparts of the wings. The upper mandible is black and the lower mandible can be pink, orange, or lilac. Males and females are similar in size and coloration.[2] A juvenile emperor penguin is similar in size and coloration to adult, but its auricular patches, chin, and throat are white.[2] Emperor Penguin chicks are covered with silver-gray down with a black head and white eye and cheek patches.[2]
Vocalization
The Emperor Penguin utilizes a complex set of calls that are critical to individual recognition between parents, offspring, and mates.[2] Its calls are known for using two frequency bands simultaneously.[3] Chicks use a frequency-modulated whistle to beg for food and to contact parents.[2]
Distribution and habitat
The Emperor Penguin has a circumpolar distribution, found almost exclusively in the Antarctic ranging from 66º to 77º south latitude. It almost always breeds on stable pack ice near the coast and up to 18 km (11 mi) offshore.[2] Breeding colonies usually occur in sheltered areas where ice cliffs and icebergs protect against the wind.[2] Only two small breeding colonies are known to occur on land.[2]
Vagrants have been recorded on Heard Island, South Georgia, and New Zealand.
Behavior
Emperor Penguins are social animals, both foraging and nesting in groups. In severe weather the penguins huddle together for protection. They may be active day or night. Mature adults travel throughout most of the year between the nesting area and foraging areas in the ocean. From January to March, Emperor Penguins disperse into the oceans, traveling and foraging in groups. It is estimated that there are at least 250,000 Emperor Penguins, distributed into as many as 40 independent Antarctic colonies. The Emperor Penguin normally dives to between 150 and 250 m (490 to 820 ft), although they can venture deeper, the deepest diving on record being 565 m (1870 ft). It can hold its breath underwater for up to 22 minutes.[4] Its swimming speed is 6 to 9 km/h (4 to 6 mph), but they can achieve up to 19 km/h (12 mph) in short bursts. On land they alternate between walking with a wobbling gait and sliding over the ice on their bellies, propelled by their feet and their flipper-like wings.
As a defense against the cold, Emperor Penguins stand in compact huddles (also known as the turtle formation) ranging in size from ten to many hundreds of birds, with each bird leaning forward on a neighbor.[5] Those on the outside tend to shuffle slowly around the edge of the turtle producing a slow churning action, giving each bird a turn on the inside and the outside. Without this behaviour male Emperor Penguins would be unable to survive the brutal Antarctic winter.
Diet
The Emperor Penguin eats primarily fish, crustaceans, and cephalopods.[6] The exact composition of the prey varies from population to population, but fish is usually the most important food source and Antarctic silverfish, Pleuragramma antarcticum, is often the most important species eaten. It searches for prey in the open water of the Southern Ocean or in ice-free areas of open water and tidal cracks in pack ice.[2] One of it feeding strategies is to dive to about 50 m (164 ft), where it can easily spot the sub-ice fish, Pagothenia borchgrevinki, swimming against the under surface of the sea-ice, which it then catches. It then dives again and repeats the sequence about half a dozen times before surfacing to breathe. It has been recorded diving to depths of 400 to 450 meters and traveling 150 to 1000 km in a single foraging trip.[2]The Emperor Penguin may also blow bubbles into the cracks in the ice to drive out the hiding fish.
Predators
In the wild, the Emperor Penguin's predators include birds, which prey on chicks and eggs, and aquatic mammals which prey upon both chicks and adult penguins. The primary bird predators are the Southern Giant Petrel and the South Polar Skua. The primary aquatic mammal predators are the Leopard Seal, and orca (killer whale). They come up from the water and through a hole in the ice, the penguins slide away from their enemies.
Reproduction
Emperor Penguins first begin to breed at approximately five years of age. Emperor penguins travel about 90 km (56 mi) inland to reach the breeding site. The penguins start courtship in March or April, when the temperature can be as low as –40°C. Emperor Penguins are serially monogamous. They have only one mate each year, and stay faithful to that mate. However, the next year, most end up with different mates. Although they attempt to locate the previous year's mate in the next breeding season, most cannot find each other and choose a new mate.dum dum
In May or June, the female penguin lays one 450 gram (1 lb) egg, but at this point her nutritional reserves are exhausted and she must immediately return to the sea to feed. Very carefully, she transfers the egg to the male, who incubates the egg in his brood pouch for about 65 days consecutively without food by surviving on his fat reserves and spending the majority of the time sleeping to conserve energy. The transfer of the egg can be awkward and difficult, and many couples drop the egg in the process. When this happens, the chick inside is immediately lost as the egg cannot withstand the low temperatures on the icy ground. To survive the cold and winds of up to 200 km/h (120 mph), the males huddle together, taking turns in the middle of the huddle. They have also been observed with their backs to the wind to conserve body heat. If the chick hatches before the mother's return, the father sets the chick on his feet and covers it with his pouch, feeding it a white, milky substance produced by a gland in his esophagus.
After about two months, the female returns. She finds her mate among the hundreds of fathers via his call and takes over caring for the chick, feeding it by regurgitating the food that she has stored in her stomach. The male then leaves to take his turn at sea. His trip is slightly shorter than before, because the melting of ice in the summer gradually decreases the distance between the breeding site and the open sea. After another few weeks, the male returns and both parents tend to the chick by keeping it off the ice and feeding it regurgitated food. About two months after the egg hatches, as the weather becomes milder, the chicks huddle in a crèche for warmth and protection, still fed by their parents.
Eventually, both the chick and parents return to the sea and spend the rest of the summer feeding there. At the end of the summer the whole inland trip is repeated for all those penguins of breeding age, while the younger ones stay at the sea edge.
Relationship with humans
Cultural references
The Emperor Penguin has been the subject of several documentaries. In 1993, the species was featured in the BBC series Life in the Freezer, hosted by David Attenborough. In 2005, the French documentary La Marche de l'empereur (released as March of the Penguins in the U.S.) spotlit the penguins' reproductive cycle. The BBC and Attenborough covered the Emperor again in the 2006 series Planet Earth. Apsley Cherry-Garrard, the Antarctic explorer said: "Take it all in all, I do not believe anybody on Earth has a worse time than an Emperor Penguin."[7] The computer-animated movie Happy Feet (2006) features Emperor Penguins as its primary characters, with one in particular that loves to dance, depicting them as endangered by a shrinking food supply. The computer-animated movie Surf's Up (2007) features a genius Emperor penguin surfer named, Zeke " Big-Z" Topanga. The NHL's Pittsburgh Penguins Franchise is named after the Emperor Penguin, And an Emperor Penguin leads the team onto the ice each year prior to the start of the first home game of the season.
Conservation
The Emperor Penguin is listed as least concern by the IUCN. Along with nine other species of penguin, it is currently being considered for placement under the US Endangered Species Act. The primary reasons for this are declining food availability due to the effects of climate change, and industrial fisheries on the crustacean and fish populations. Other reasons for their placement on this list include such things as disease, foreign and introduced predators (this is more so for the other species of penguin than it is the Emperor), habitat destruction, and disturbance at breeding colonies by humans. Of particular concern is the impact of tourism.[8]
Further reading
- Deguine, Jean-Claude. 1974. Emperor Penguin: Bird of the Antarctic. The Stephen Greene Press, Vermont.
- Rivolier, Jean. 1956. Emperor Penguins. Elek Books, London.
- Williams, T. (1995). The Penguins. Oxford, England: Oxford University Press.
- "Emperor Penguin". Great Book of Birds. Philadelphia: Courage Books. 1997.
- National Geographic CritterCAM additional feature on DVD version of March of the Penguins
- Willy Puchner, Penguins - Traveling the World
References
- ^ Template:IUCN2006 Database entry includes justification for why this species is of least concern
- ^ a b c d e f g h i j k l University of Michigan Museum of Zoology. "Aptenodytes forsteri".
{{cite web}}: Unknown parameter|accessmonthday=ignored (help); Unknown parameter|accessyear=ignored (|access-date=suggested) (help) - ^ Robisson P. (1992). "Vocalizations in Aptenodytes Penguins: Application of the Two-voice Theory" Auk 109(3): 654-658 [1]
- ^ Ward, Paul. "Emperor Penguins".
{{cite web}}: Unknown parameter|accessmonthday=ignored (help); Unknown parameter|accessyear=ignored (|access-date=suggested) (help) - ^ Pinshow B., Fedak M.A. , Battles D.R, & Schmidt-Nielsen K. (1976) "Energy expenditure for thermoregulation and locomotion in emperor penguins" American Journal of Physiology 231(3): 903-912
- ^ Cherel Y. & Kooyman G. L. (1998) "Food of emperor penguins ( Aptenodytes forsteri ) in the western Ross Sea, Antarctica" Marine Biology 130(3): 335-344 doi:10.1007/s002270050253
- ^ Apsley Cherry-Garrard. From the Introduction to The Worst Journey in the World.
- ^ Burger J. & Gochfeld M. (2007) "Responses of Emperor Penguins ( Aptenodytes forsteri ) to encounters with ecotourists while commuting to and from their breeding colony". Polar Biology 30(10): 1303-1313 doi:10.1007/s00300-007-0291-1
External links
- University of Michigan info site with citations for specific studies
- Photographs of Emperor penguins
- Morphology of the Emperor Penguin including 3D computed tomographic (CT) animations of skeletons
- Emperor Penguin videos on the Internet Bird Collection
- Emperors of the Extreme article from Scripps Institution of Oceanography