This picture taken on March 31, 2014 shows residents of the Kakira village, in the Jinja District of eastern Uganda, gathering to look at a crocodile that was captured by Uganda Wildlife Authority (UWA) staff. (Photo by Peter Busomoke/AFP Photo)

Chimpanzee Viktoria bites into an Easter egg as she sits in her enclosure at the zoo in Hanover, central Germany on April 3, 2014. The egg was filled with roots and fruits and a trophy from an Easter egg hunt for the zoo animals as the Easter vacation started in this German region of Lower Saxony. (Photo by Holger Hollemann/AFP Photo/DPA)

A male big brown bat in flight is shown in this University of Maryland photo released on March 28, 2014. Researchers have learned that male big brown bats in flight use a special call, different from the echolocation calls they use for navigation, to warn other foraging males away from insect prey that they are claiming for themselves. (Photo by Jessica Nelson/Reuters/Auditory Neuroethology Laboratory/University of Maryland)

Employees of the Sevastopol State Oceanarium train dolphins, in Sevastopol, Crimea, Sunday, March 30, 2014. A Soviet-era military program training dolphins and seals for combat will be revived in Crimea after its annexation by Russia, according to Russian state media. (Photo by Pavel Golovkin/AP Photo)

An Australian Koala looks at a camera as it sits atop a branch in its enclosure at Wild Life Sydney Zoo April 3, 2014. Images from the camera, which are triggered by the koala's movements, are displayed on a nearby small screen which the zoo is promoting as a koala “selfie”. (Photo by David Gray/Reuters)

An Australian Koala, that was born with a damaged eye, looks at a camera as it sits atop a branch in its enclosure at Wild Life Sydney Zoo. (Photo by Reuters/David Gray)

Afghan men load chairs on a donkey as they prepare to transport ballot boxes and other election material to polling stations which are not accessible by road in Shutul, Panjshir province, April 4, 2014. The Afghan presidential elections will be held on April 5. (Photo by Ahmad Masood/Reuters)

A Lemur catta, also known as ring-tailed lemur, with its three-week-old cub clinging to its back sits on a tree at the Schoenbrunn zoo in Vienna April 4, 2014. (Photo by Heinz-Peter Bader/Reuters)

Aurora, a four-year-old female polar bear, swims in a pool for the first time in the season, with the air temperature at about 20 degrees Celsius (68 degrees Fahrenheit), at the Royev Ruchey zoo in a suburb of Russia's Siberian city of Krasnoyarsk, April 4, 2014. Two female polar bear cubs, Aurora and Victoria, were found without their mother in Russia's Taymyr Peninsula on the Arctic Ocean coast in May 2010 and were later brought to the zoo in Krasnoyarsk, according to zoo representatives. (Photo by Ilya Naymushin/Reuters)

A sniffer dog trained to search for explosives, performs during an awareness campaign for schoolchildren at the United Nations Interim Force in Lebanon (UNIFIL) headquarters in the town of Naqoura in southern Lebanon April 4, 2014. U.N. peacekeepers in southern Lebanon held an educational campaign for schoolchildren teaching them to identify mines and unexploded cluster bombs to commemorate international mine awareness day. (Photo by Ali Hashisho/Reuters)

Riders and horses clear “The Chair” in the “Supporting The Everton In The Community Steeple Chase” during the Grand National horse racing meeting at Aintree, northern England April 4, 2014. (Photo by Toby Melville/Reuters)

A young spectacled bear, which was born a few months ago and does not have a name yet, plays in his open-air enclosure at the zoo in Duisburg, Germany, 31 March 2014. Spectacled bears are the only bears originally living in South America. (Photo by Roland Weihrauch/EPA)

A baby spectacled bear plays in its enclosure at the zoo in Duisburg, western Germany, on March 31, 2014. In the wild, spectacled bears live in South America. (Photo by Roland Weihrauch/AFP Photo/DPA)

Two ten-day-old Patas Monkey babies and their mothers sit in the sun at the zoo in Olomouc, Central Moravia, Czech Republic on March 31, 2014. (Photo by Radek Mica/AFP Photo)

A ten-day-old Patas Monkey baby holds on to its mothers at the zoo in Olomouc, Central Moravia, Czech Republic on March 31, 2014. (Photo by Radek Mica/AFP Photo)

A couple of moor frogs sit in a pond during spawning season on April 1, 2014 in Leipzig, eastern Germany. Due to drainage of moors and wetlands, the habitat of the species is getting smaller. (Photo by Sebastian Willnow/AFP Photo/DPA)

A polar bear is pictured during the opening day of the new polar area at the zoo of Mulhouse on April 2, 2014. (Photo by Sebastien Bozon/AFP Photo)

A hare runs over a field near Sachsendorf, eastern Germany, on April 3, 2014. (Photo by Patrick Pleul/AFP Photo/DPA)

A child watches as Civa Sumac, a white Bengal tiger, explores her new glass-fronted enclosure at Huachipa zoo in Lima, on April 3, 2014. (Photo by Mariana Bazo/Reuters)

Callie Jones shuts her eyes as a large blue Morpho butterfly rests on her face during a media call for a butterfly exhibition in a temporary venue outside the Natural History Museum Monday, March, 31, 2014. (Photo by Alastair Grant/AP Photo)

A pigeon rests on a wild iguana in a tree inside Seminario Park in Guayaquil, Ecuador, Thursday, April 3, 2014. Pigeons coexist with the wild iguanas at this park in the middle of the city surrounded by savannah. (Photo by Dolores Ochoa/AP Photo)

Photographers take pictures of “Thug” the Pygmy Hippo exploring his new enclosure during a photocall at the zoo in London, Thursday, April 3, 2014. Thug and his lifelong Pygmy Hippo companion Nicky were unveiled to the media in their new home Thursday, which opens for public viewing on April 5 as part of the zoo's “Into Africa” exhibit. (Photo by Matt Dunham/AP Photo)

A Yorkshire Terrier leaves the hall during an International dog show in Schoenefeld near Berlin, Germany, Sunday, March 30, 2014. (Photo by Markus Schreiber/AP Photo)

Nguyen Minh Nghia, owner of Pet Cafe, looks on as Hieu Tran, a customer, holds an iguana at the cafe in Hanoi April 1, 2014. The cafe, Hanoi's first pet cafe, houses wild animals such as snakes, hedgehogs and tarantulas and allows customers to directly interact them. (Photo by Reuters/Kham)

Duncan, a 9 month- old Boxer, runs in the backyard Thursday April 3, 2014 in Vancouver, Wash. Duncan was born with deformed rear legs that were amputated to remove the dead weight. The 9-month-old boxer belongs to Amanda Giese and Gary Walters, who run a non-profit animal rescue called Panda Paws Rescue out of their home in the Clark County community of Felida. Duncan has become an instant YouTube sensation. (Photo by Troy Wayrynen/AP Photo/The Columbian)

Thug, the 17-year-old pygmy hippo, explores his new enclosure in London Zoo in central London, on April 3, 2014. The new exhibit will be home to hippos Thug and 19-year-old Nicky, with heated pools and specially designed gardens. (Photo by Philip Toscano/PA Wire)

A fisherman carries a swordfish on his head from the Indian Ocean waters to the market in Somalia's capital Mogadishu March 31, 2014. (Photo by Ismail Taxta/Reuters)

Moor frogs sit in a pond in Leipzig, eastern Germany. Due to drainage of moors and wetlands, the habitat of the species is getting smaller, on April 1, 2014. (Photo by Sebastian Willnow/AFP Photo)

Rescue dog Tryon, muddied from the day's work, stands with his handler near the west side of the mudslide on Highway 530 near mile marker 37 in Arlington, Wash., on Sunday, March 30, 2014. Periods of rain and wind have hampered efforts the past two days, with some rain showers continuing today. Last night, the confirmed fatalities list was updated to 18, with the number of those missing falling from 90 to 30. (Photo by Rick Wilking/AP Photo)

In this picture taken Sunday, March 30, 2014, eleven year old bear mother Luna, rear watches one of her cubs in front of their cave in the Bavarian Forest National Park near Grafenau, southern Germany. The gender of the three cubs could not be determined yet because the mother doesn't let anyone near her offspring. (Photo by Frank Bietau/AP Photo/DPA)

A meerkat guards colored Easter eggs at the zoo in Hannover, Germany, Thursday, April 3, 2014. The zoo keepers surprised the animals with an Easter egg hunt on the first day of the Lower-Saxon Easter school holidays. (Photo by Holger Hollemann/AP Photo/DPA)

Sheep race in the Lamb National at Ascot Country Fair Raceday at Ascot Racecourse in Ascot, England, on March 30, 2014. (Photo by Tristan Fewings/Getty Images for Ascot Racecourse)

A red-eared turtle swims in the pond of the turtle enclosure during sunshine in the zoo in Duisburg, Germany, Monday, March 31, 20145. (Photo by Roland Weihrauch/AP Photo/DPA)

A child looks at a polar bear during the opening day of the new polar area at the zoo of Mulhouse on April 2, 2014. (Photo by Sebastien Bozon/AFP Photo)

A border collie guides gooses during a competition on the third day of an international dog show at the fair ground in Berlin March 30, 2014 in Berlin. (Photo by Johannes Eisele/AFP Photo)

Thug, a 17-year-old pygmy hippo, moves around in a new enclosure equipped with solar panels at London Zoo in London on April 3, 2014. Often mistaken for its larger cousin, the pygmy hippo is much smaller than the common hippopotamus, they have a smaller head and eyes with ears to the side of the head. Classed as endangered, pygmy hippos are under constant threat from poaching and habitat-loss in the wild. (Photo by Adrian Dennis/AFP Photo)

Giant panda Hao Hao eats during a visit by the Chinese President at Paira Daiza Park in Brugelette, Belgium, Sunday, March 30, 2014. Two giant panda's, Xinhui and Hao Hao, have been loaned to the zoo by the Chinese authorities for a period of 15 years. (Photo by Laurent Dubrule/AP Photo)

A dog, trimmed to look like a lion, walks on the rooftop of the Mitsukoshi department store in Tokyo on April 5, 2014. One hundred lion looking dogs gathered to celebrate the 100th anniversary of Mitsukoshi department store's mascot lion. (Photo by Yoshikazu Tsuno/AFP Photo)