In this photo provided by the San Francisco Zoo, a reticulated giraffe calf nuzzles Ron Amiot, an animal keeper at the San Francisco Zoo, Thursday, April 2, 2009 in San Francisco, Calif. The calf was born that morning at sun-up to Kristin. Giraffe females give birth standing up after the 14 to 15 month gestation period, with a six foot drop for the Calf's entrance into the world. (AP Photo/George Nikitin, San Francisco Zoo) #

Three Sumatran tiger cubs play in the tiger exhibit at the San Diego Zoo's Wild Animal Park on March 25, 2009. The trio, born on November 13, 2008, was only recently allowed in the big outdoor enclosure for public viewing. The Sumatran tiger is listed as endangered by the International Union for Conservation of Nature, or IUCN. Only between 300 and 400 Sumatran tigers are left in the wild on the island of Sumatra in Indonesia, mostly in national parks. There are only 350 in managed care. (KEN BOHN/AFP/Getty Images) #

The sun shines on the skin of a hippopotamus in its enclosure in the Zoo in Berlin, Germany on Friday, April 3, 2009. (AP Photo/Franka Bruns) #

White rhinoceros baby Naruna explores its enclosure with her mother Rebecca at the Serengeti Park in Hodenhagen, northwestern Germany, on April 8, 2009. Naruna was born on November 22, 2008 at the park. (NIGEL TREBLIN/AFP/Getty Images) 12natural #

A giant panda sits in the Olympic Games Panda House at Beijing Zoo, March 22, 2009. Eight giant pandas flown to Beijing last May to add cheer to the Olympics return to their hometown in southwest China's Sichuan Province on Sunday, Xinhua reported. (REUTERS/Jason Lee) #

A baby kangaroo named Tijana peers from the incubator in its enclosure in Belgrade Zoo in Serbia on April 16, 2009. Her mother, after being scared by an emu, ran away and Tijana fell from her pouch. Now Tijana, who cannot survive outside a pouch, must stay in a special incubator, where the temperature remains a constant 35 degrees Celsius. Biologists have fashioned a set of canvas pouches for her, and she is fed every two hours with a special milk from US and Germany. (REUTERS/Ivan Milutinovic) #

In this photo provided by the Chicago Zoological Society, Sophia, a 27-year-old orangutan, and her unnamed 6-month-old baby female enjoy the day at the Brookfield Zoo in Brookfield, Ill., on Thursday, April 9, 2009. (AP Photo/Chicago Zoological Society, Jim Schulz) #

A dolphin checks out the photographer while it swims in its pool at the Nuremberg Zoo in the southern German city of Nuremberg, germany on April 16, 2009. (TIMM SCHAMBERGER/AFP/Getty Images) #

Dromedary mother Jasmin sniffs her baby Jamila in the outdoor enclosure at the Berlin Zoo, Tuesday, April 7, 2009. Jamila was born on April 2, 2009. (AP Photo/Maya Hitij) #

Gorilla infant Kiburi sleeps on her mother Safiri's back, during sunny weather at the zoo, in Duisburg, Germany, Wednesday, April 8, 2009. (AP Photo/Martin Meissner) #

A baby leopard sits in a basket on April 8, 2009 at the Hagenbeck zoo in Hamburg, northern Germany. The two North Chinese leopards (Panthera pardus japonensis) were born six weeks ago at the zoo. The North Chinese Leopard is an endangered species. No-one knows for sure how many North Chinese Leopards there are in the wild, which makes it difficult to protect them. There are only 100 in captivity, and new blood lines are needed in order to continue a healthy population of the cats. (ROLAND MAGUNIA/AFP/Getty Images) #

Zhang Jie and Zhongni, two six-week-old North Chinese Leopards are seen during a name giving ceremony at Hagenbeck Zoo on April 8, 2009 in Hamburg, Germany. (Joern Pollex/Getty Images) #

An ostrich eats a roll at the Serengeti Park in Hodenhagen, northwestern Germany, on April 8, 2009. Around 1,500 animals live in the park with an area of approximately 110 hectares. (NIGEL TREBLIN/AFP/Getty Images) #

An employee of a mobile zoo throws meat to a lion and an Amur tiger on April 3, 2009. The meat was donated by locals in the town of Sosnovoborsk, northeast of the Siberian city of Krasnoyarsk, Russia. Some 30 animals from a mobile zoo were left in dire conditions, going without food and care for days, after the Russian migration service deported the zoo's Armenian owners from the country because of their expired visas, local media reported. The owners had taken their zoo, which included an Amur tiger, a lion, and a lynx, on tours around Russia and intended to spend the winter in the small Siberian town. (REUTERS/Ilya Naymushin) #

A young Asiatic brown bear squeezes its head under the bars of its four square meter mobile enclosure in the town of Sosnovoborsk, Russia on April 3, 2009. The bear is among some 30 animals left without food and care for days, after the Russian migration service deported the zoo's Armenian owners from the country because of their expired visas. (REUTERS/Ilya Naymushin) #

Cezar, a lion relocated from a Romanian zoo takes in his new surroundings at Lions Rock big cat sanctuary near Bethlehem in South Africa March 14, 2009. Cezar is one of a group of seven lions relocated from Austrian and Romanian zoos by international animal rights foundation Four Paws (Vier Pfoten). (REUTERS/Mike Hutchings) #

Senior zookeeper Laura Pelrine gets the attention of a young ring-tailed lemur, born February 18 at Franklin Park Zoo in Boston, Friday, April 3, 2009. The lemur measures 6 inches and weighs about 5 ounces. (Globe Staff Photo/Wendy Maeda) #

This April 8, 2009 Smithsonian National Zoo handout photo shows US actor Harrison Ford and fiance actress Calista Flockhart, along with her son Liam, as they get up-close to the Smithsonian's National Zoo's Nile hippopotamus, Happy. Ford fed the 5,000-pound hungry hippo while his soon-to-be family looked on with animal keeper Jay Tee Taylor. (JESSIE COHEN/AFP/Getty Images) #

A Harlequin frog is seen at the El Nispero Zoo in El Valle town, Panama April 16, 2009. More than 32 species of amphibians in danger of extinction are being held in captivity to protect them against the contamination of their environment and the Chytrid fungus that has killed a great percentage of amphibia worldwide, the Zoo revealed. (REUTERS/Alberto Lowe) #

Gorilla mother Tamani shows her newborn baby to visitors in Blijdorp Zoo in Rotterdam on April 12, 2009. The silverback gorilla named Bokito, who went on a rampage two years ago in the Blijdorp Zoo, is the father of the newborn baby. (Marten van Dijl/AFP/Getty Images) #

A baby Giraffe stands next to its mother in the zoo in Hanover, Germany on March 13, 2009. The Giraffe young was born on February 24, 2009. (NIGEL TREBLIN/AFP/Getty Images) #

Brown bear Pedro lies on the ground as zoo visitors look on and cast their shadows on the ground in Bern, Switzerland on Good Friday, April 10, 2009. (AP Photo/KEYSTONE/Peter Klaunzer) #

Greg Clark of Wild at Heart shows one of the burrowing owls about to be released inside a temporary tent constructed near Kingman, Ariz. on Saturday March 14, 2009. An all-volunteer, nonprofit organization dedicated to wildlife conservation, started the process of relocating several displaced burrowing owls to their new home northeast of Kingman on Saturday. (AP Photo/Kingman Daily Miner, JC Amberlyn) #

A Siberian Tiger (Panthera tigris altaica) roars as it feeds at the zoo of Zurich, Switzerland, Wednesday, April 15, 2009. (AP Photo/Keystone, Urs Flueeler) #

North, a Little Penguin, is pushed into the sea by veterinarian Amy Twentyman of the Taronga Zoo at North Curl Curl beach in Sydney, Australia on March 20, 2009. The zoo released back into the ocean two adult Little Penguins after they had rested and been cared for at Taronga's Wildlife hospital. (REUTERS/Daniel Munoz) #

An adult Little Penguin named North returns to the sea following a period of care at Taronga Zoo's Wildlife Hospital, at North Curl Curl Surf Life Saving Club on March 20, 2009 in Sydney, Australia. North and South, a pair of Little Penguins, were found at different beaches by members of the public, one on Christmas Day at Terrigal and the other two months later at Cronulla. (Brendon Thorne/Getty Images) #

Charlie, a male sumatran orangutan lazes next to a palm leaf on Wednesday, April 8, 2009 at the Singapore Zoo. (AP Photo/Wong Maye-E) #

A Yellow Mongoose is anesthetized before undergoing a health check in London Zoo's veterinary surgery on March 11, 2009 in London, England. The first part of the procedure checks the animals ears, eyes, teeth, feet and its gender. The small mammal which originates from southern Africa is one of three from Marwell Zoo, which will make up part of a new Animal Adventure exhibit to be opened on April 3, 2009 at the park. (Dan Kitwood/Getty Images) #

The teeth of a yellow mongoose are checked in london Zoo's veterinary hospital while undergoing a health check on March 11, 2009 in London, England. London Zoo's veterinary hospital sees hundreds of animals through its doors every year ranging from frogs to gorillas. (Dan Kitwood/Getty Images) #

The eyes of a dominant male western lowland gorilla stare at a visitor at the primate sanctuary run by the Cameroon Wildlife Aid Fund in Mefou National Park, just outside the capital Yaounde, March 21, 2009. The United Nations has designated 2009 as the year of the gorilla and has launched efforts across Africa to preserve the endangered species found in central African nations including Cameroon, Democratic Republic of Congo, Rwanda and Uganda. (REUTERS/Finbarr O'Reilly) #

With facecloth on head, male Baikal Seal Billy performs "a dip in a hot spring" as he holds a sake bottle in a basin with flipper at a pool in the Hakone-en aquarium in Hakone, west of Tokyo, Tuesday, March 17, 2009. It took three months for six-year-old Billy to master this performance, a traditional Japanese style of soaking in a hot spring. (AP Photo/Itsuo Inouye) #

Pagi, right, a female Bornean sun bear cub whose name means "morning" in a Malayan dialect, licks her brother, Palu, who is named after a valley in Borneo, as they made their public debut at the San Diego Zoo on Monday, March 16, 2009. The twins are only the third Bornean sun bear litter to be born in North America, all of which have occurred at the San Diego Zoo, where researchers are studying reproductive biology and maternal care of the sun bear. (AP Photo/San Diego Zoo, Tammy Spratt) #

Polar bears Bill, right, and Lara react during their first meeting, at the Zoom Erlebniswelt zoo, in Gelsenkirchen, Germany, Friday, April 17, 2009. Bill came from the zoo in Bruenn, Czech Republic, as a new partner for Lara. (AP Photo/Martin Meissner) #

An arctic fox is released into his new residence in Rotterdam Zoo on April 8, 2009. The Dutch Zoo organisation is starting a new campaign in an attempt to make people aware of the threat to predators like the arctic fox in Europe. (VALERIE KUYPERS/AFP/Getty Images) #

16-year-old male mandrill "Pablo", 10-year-old "Zora" and their four-week-old baby play in their enclosure on March 20, 2009 at Munich's zoo Tierpark Hellabrunn. (JOERG KOCH/AFP/Getty Images) #

Five-day-old elephant Ko Raya looks out of her enclosure beside her mother, 22-year-old Asian elephant Pang Pha, as the pair were presented to the public at Berlin's Zoologischer Garten zoo March 20, 2009. Ko Raya was born at the zoo and is Pang Pha's third offspring. (STEFFI LOOS/AFP/Getty Images) #