Green Sea Turtles in the waters of Bora Bora, Tahiti. The gender of sea turtle eggs are determined by temperature, which means global warming would upset the natural gender balance. (Michele Westmorland)

A grizzly bear looks on at St-Felicien Wildlife Zoo in St-Felicien, Quebec September 24, 2008. Parks Canada estimates that up to 20,000 grizzly bears remain in western Alberta, the Yukon and Northwest Territories and British Columbia. The Committee on the Status of Endangered Wildlife in Canada lists grizzly bear as a "Special Concern". (REUTERS/Mathieu Belanger)

A blacktip shark is seen in this undated handout image released on October 10, 2008. Scientists using DNA testing have confirmed the second-known instance of "virgin birth" in a shark - a female of this species named Tidbit that produced a baby without a male shark. The shark died after being removed from the tank at a Virginia aquarium for a veterinary examination, and a subsequent necropsy revealed that Tidbit was carrying a fully developed shark pup nearly ready to be born. Virgin birth, known scientifically as parthenogenesis, also has been documented in Komodo dragons, snakes, birds, bony fish and amphibians. (REUTERS/Matthew D. Potenski)

A zebra eyes visitors at the zoo in Chisinau, Moldova Sunday Sept. 28, 2008. (AP Photo/John McConnico)

In this photo released by the Wildlife Conservation Society, a Chilean pink flamingo preens its feathers at the Bronx Zoo in New York, Wednesday, Sept. 10, 2008. (AP Photo/WCS, Julie Larsen Maher)

A giant kangaroo rat is seen in this undated photo provided by the Nature Conservancy. When the San Joaquin Valley was an arid grassy plain, giant kangaroo rats were the seed-hording gardeners that helped propagate native plants. Now scientists are turning to satellite technology to determine how climate change and rainfall patterns are affecting the endangered species' remaining habitat. (AP Photo/University of California, Berkeley, John Roser)

Indah, a three week old Malayan tapir chews on a twig during her first photocall at Edinburgh zoo, Scotland October 16, 2008. Malayan tapirs, which are an endangered species, are hoofed animals related to rhinos and horses and are found in the forests of Malaysia, Thailand, Burma and Sumatra. (REUTERS/David Moir)

Polar bear cub "Wilbaer", left, plays with his mother Corinna in the outdoor enclosure at Stuttgart Zoo, Southern Germany, on Tuesday June 10, 2008. (AP Photo/Daniel Maurer)

Narwhals seen along the floe edge in Arctic Bay, Canada. The whales are pushing under the ice to feed on cod. They come up in seal holes and rotten ice in order to catch a breath. This undated photo is part of an exhibit titled "Irreplaceable: Wildlife in a Warming World," recently shown at the Peerless building in downtown Providence, Rhode Island. (Paul Nicklen/National Geographic Image Collection)

This undated handout picture shows a Common Kingfisher with a fish in his beak. Germany's environmental protection organisations NABU (Naturschutzbund) and LBV (Landesbund fuer Vogelschutz) announced on October 10, 2008 that they had nominated the Common Kingfisher as "Bird of the Year 2009". (MANFRED DELPHO/AFP/Getty Images)

Amur tigers Sasha (L) and Yuri, recently transferred from Edinburgh Zoo, fight over food in their new enclosure at The Highland Wildlife Park in Kingussie, near Aviemore in Scotland on October 6, 2008. With only 500 Amur tigers remaining in the wild around the Amur river valley in the far east of Russia, it is hoped that the pair will continue to contribute to the worldwide breeding programme from their new home in the Scottish Highlands. (REUTERS/David Moir)

In this photo released by the Wildlife Conservation Society, a blue poison dart frog is perched on a rock at the Bronx Zoo, Tuesday, Sept. 9, 2008 in New York. The frog's blue color serves and an indicator to other species that its secretions are toxic. (AP Photo/WCS, Julie Larsen Maher)

A baby Orangutan named Isalie is seen in her enclosure, beign held by her mother, Siti in the Munich Zoo on October 7, 2008. Isalie was born in the zoo in Hellabrunn on July 14, 2008. (AP Photo/Christof Stache)

A lion cub named Mandisa (left), watches her brother Masamba chew on a limb as the two play at the NEW Zoo on Thursday. Oct. 9, 2008 in Suamico, Wisconsin. The pair were born on July 19, 2008. (AP Photo/Green Bay Press-Gazette, Corey Wilson)

In this photo released by the Wildlife Conservation Society, a Victoria crowned pigeon is seen at the Bronx Zoo in New York, Wednesday, Sept. 10, 2008. (AP Photo/WCS, Julie Larsen Maher)

Emperor Penguins are seen in an undated photograph from an exhibit titled "Irreplaceable: Wildlife in a Warming World," recently shown at the Peerless building in downtown Providence, Rhode Island. Warmer temperatures in Antarctica are causing declines in krill, one of the penguin's main food source. (Kevin Schaffer)

Keyah, a baby white rhino born on October 10, 2008 and weighing 30kg, stands by its mother on October 15, 2008 at the Cerza zoo in Hermival-les-Vaux, France. The birth in captivity of white rhinos are very rare, one to two per year in Europe. (MYCHELE DANIAU/AFP/Getty Images)

Moyo, a 3-year-old male cheetah from South Africa, chases a lure during the Cheetah Dash event at the Animal Ark in Reno, Nevada on Sunday, Sept. 21, 2008. Animal Ark runs the cheetahs regularly to keep them in good health. (AP Photo/Nevada Appeal, Kevin Clifford)