In this undated photo provided by Minden Pictures, a drill (Mandrillus leucophaeus), left, challenges a dominant male, right, for leadership of a harem at a sanctuary in Calabar, Cross River State, Nigeria. Animal Planet on Tuesday, March 31, 2015, will unveil a slate of programming for the coming year which ranges wildly from conservation stories and natural-history documentaries to pet love and epic ventures reconnecting with nature. Among the channels new shows is a series documenting the efforts of Peter Jenkins, known as Nigeria's leading wildlife warrior, whose mission is to protect the exotic animals of Africa's dangerous Cross River region from poachers and other human threats. (Photo by Cyril Ruoso/AP Photo/Minden Pictures/JH Editorial)

In this March 26, 2015, image provided by Randall Brown of Multnomah County Animal Services, a pair of chickens, dyed pink, are photographed in Portland, Ore. The animals were picked up earlier this week running loose in the city's waterfront park. Multnomah County Animal Services says the owner, Bruce Whitman of Portland, told the agency he used food coloring, beet juice and Kool-Aid to dye the two birds, then released them for a while to “make people smile”. Officials say they told Whitman about the dangers of releasing birds in public places. He was billed for the time the chickens were in the county's care. (Photo by Randall Brown/AP Photo/Multnomah County Animal Services)

Miniature Mediterranean donkeys play in their enclosure in the Kids' Farm at the Smithsonian's National Zoological Park, Saturday, March 28, 2015, in Washington. (Photo by Carolyn Kaster/AP Photo)

A fox runs in front of 10 Downing Street on March 30, 2015 in London, England. Campaigning in what is predicted to be Britain's closest national election in decades will start after Queen Elizabeth II dissolves Parliament today. (Photo by Carl Court/Getty Images)

A Miniature Dachshund (L) wears a duck bill-shaped dog muzzle while sitting in a stroller with another Miniature Dachshund at the “Interpets” international pet fair in Tokyo, Japan, April 2, 2015. (Photo by Kiyoshi Ota/EPA)

Sea lions lay on marina docks in Astoria, Oregon March 29, 2015. More than 2,300 California sea lions have taken over the docks of the coastal community and are expected to stay until the smelt and salmon runs they feed on are finished in late May, according to officials. (Photo by Steve Dipaola/Reuters)

Officers from the Sumatran Orangutan Foundation Lestari and the Orangutan Information Centre check the health of a rescued female Sumatran orangutan found isolated in an oil palm planation in the village of Kuala Musam, Langkat, North Sumatra, March 30, 2015 in this photo taken by Antara Foto. (Photo by Irsan Mulyadi/Reuters/Antara Foto)

In this March 26, 2015 photo provided by the National Park Service, female Sierra Nevada bighorn sheep are released into the backcountry of Yosemite National Park, Calif. A total of 12 bighorn sheep were released into the Cathedral Range in Yosemite's backcountry during a multiagency operation, which included California Department of Fish and Wildlife, Yosemite National Park, Sequoia National Park, and Inyo National Forest. For the first time in a century, bighorn sheep occupy the full range of California's Sierra Nevada mountains, which wildlife officials said Monday, March 30, 2015, puts the endangered animal that neared extinction on a path to recovery. (Photo by Steve Bumgardner Yosemite Conservancy/AP Photo/National Park Service)

A bear cub leans on a breeder's leg during a rescued animal release event, in Kunming, Yunnan province, April 2, 2015. About 93 wild animals rescued from local markets and restaurants recently by police and animal protection group are being transported to a national park in Puer to be released back to the wild, according to local media. (Photo by Wong Campion/Reuters)

Asiatic Water Buffalos look curiously at forest officials (unseen) while they conduct a rhino census at the Kaziranga National Park in Assam state, India, 25 March 2015. Kaziranga is closed to tourists for the next two days while a census, conduicted every two years, of the rhinos commencing 25 March is underway, in a previous census in 2013 in the park the population of the Indian rhinos was 2329. (Photo by EPA/Stringer)

A chimpanzee holds a paper Easter egg filled with some treats on March 25, 2015 at the zoo in Hanover, central Germany. (Photo by Jochen Luebke/AFP Photo/DPA)

An english bulldog is pictured in the English garden on March 29, 2015 in Munich, Germany. (Photo by Peter Kneffel/AFP Photo/DPA)

Lemurs feed from hollowed out papier mache eggs filled with steamed vegetable as they celebrate Easter with an Easter egg hunt at London Zoo in Regent's Park, London on April 2, 2015. (Photo by Yui Mok/PA Wire)

The black rhino baby, that has not been named yet, stands in its enclosure in the zoo in Magdeburg, eastern Germany, Thursday April 2, 2015. The little male rhino was born on on March 25, 2015. (Photo by Jens Wolf/AP Photo/DPA)

At the Wells Fargo family farm at the Minnesota Zoo, two little piglets got to know each other as Logan Camp looked in the pen, Apple Valley, Minn., Wednesday, April 1, 2015. (Photo by Richard Tsong-Taatarii/AP Photo/The Star Tribune)

A one-month-old hippopotamus cub lies beside its mother at a zoo in Jinan, capital of east Chinas Shandong Province, March 31, 2015. (Photo by Caters News/Xinhua)

In this March 18, 2015 photo provided by the Chicago Zoological Society, Kecil, a 1-year-old orangutan, hugs his surrogate mom, Maggie, at Brookfield Zoo's Tropic World in Brookfield, Ill. Since his arrival in June 2014, Kecil has been behind the scenes bonding with Maggie, as well as developing the skills he'll need before having access to the habitat in Tropic World. Zoogoers will be able to see Kecil for the first time beginning the weekend of April 4-5. (Photo by Jim Schulz/AP Photo/Chicago Zoological Society)

In this March 18, 2015 photo provided by the Chicago Zoological Society, Kecil, a 1-year-old orangutan, has the attention of his surrogate mom, Maggie, at Brookfield Zoo's Tropic World in Brookfield, Ill. (Photo by Jim Schulz/AP Photo/Chicago Zoological Society)

In this March 18, 2015 photo provided by the Chicago Zoological Society, Kecil, a 1-year-old orangutan, climbs inside Brookfield Zoo's Tropic World in Brookfield, Ill. (Photo by Jim Schulz/AP Photo/Chicago Zoological Society)

In this March 18, 2015 photo provided by the Chicago Zoological Society, Kecil, a 1-year-old orangutan, hangs out with his surrogate mom, Maggie, at Brookfield Zoo's Tropic World in Brookfield, Ill. (Photo by Jim Schulz/AP Photo/Chicago Zoological Society)

This March 14, 2015 handout photo shows twin African pygmy goat kids at the Maryland Zoo in Baltimore. The twins, born at the zoo March 10, made their public debut Thursday. The zoo says the babies have been behind closed doors for the last three weeks bonding with their mother. (Photo by Jeffrey F. Bill/AP Photo/The Maryland Zoo)

Camels race during Al Marmoom Heritage Festival at the Al Marmoom Camel Racetrack on April 2, 2015 in Dubai, United Arab Emirates. The festival promotes the traditional sport of camel racing within the region. (Photo by Francois Nel/Getty Images)

Camels race during Al Marmoom Heritage Festival at the Al Marmoom Camel Racetrack on April 2, 2015 in Dubai, United Arab Emirates. (Photo by Francois Nel/Getty Images)

A runaway rhinoceros travels along a road in Hetauda, Makawanpur district some 40kms south-west of Kathmandu on March 30, 2015. A runaway rhinoceros escaped from a wildlife reserve and ran through a town in central Nepal, terrifying commuters as its rampage left one dead and six injured, police said. A local police official told AFP the rhino escaped from the unfenced Parsa Wildlife Reserve and wandered some 20 kilometres into neighbouring Makwanpur district, shocking onlookers as it ran through the streets, chasing vehicles and people. (Photo by Bidur Giri/AFP Photo)

The 4-month-old polar bear cub makes its first experience with snow at his enclosure at the zoo in Rostock, northern Germany, Tuesday, March 31, 2015. Some 3,000 emails, letters and calls recently reached the zoo during its search for a name of the young male bear. On Tuesday he was given the name Fiete. (Photo by Bernd Wuestneck/AP Photo/DPA)

A Bengal cat is examined by a jury member at the World Cat show in Athens on March 29, 2015. (Photo by Louisa Gouliamaki/AFP Photo)

A duck takes a leap over a small waterfall in Carroll Creek at Baker Park on April 1, 2015 in Frederick, Md. (Photo by Ricky Carioti/The Washington Post)

A handout picture made available by the Australian Reptile Park on 03 April 2015 shows King Cobra Raja being approached by an animal keeper before being milked for venom at the Australian Reptile Park in Somersby, on the New South Wales' Central Coast, Australia, 02 April 2015. Enough to fill a shot glass, close to 500 milligrams of venom was collected from the eight kilogram snake. (Photo by Greg Marsh/EPA/Australian Reptile Park)

A picture made available on 29 March 2015 shows polar bear Lars at the Rostock Zoo in Rostock, Germany, 26 March 2015. The father of famed polar bear Knut and the latest polar bear cub in Rostock will embark on a journey on 01 April 2015. Lars will help produce more polar bear cubs in Aalborg, Denmark. (Photo by Bernd Wuestneck/EPA)

“Rin-chan”, an 8-year-old female dog who is paralyzed in her hind legs has an auxiliary wheel attached to her body to aid her walking training at the nursing facility Pet Care Service Let's in Tokyo on March 25, 2015. A Japanese law amendment in 2013 resulted in the responsibility and obligations of owners and pet suppliers being enhanced which means owners now have a responsibility to continue to care for their pets until they pass away. Pet funerals are common in Japan, a nation of dog lovers, where animals are often cremated and the ashes kept in the living room along with a picture of the deceased. (Photo by Kazuhiro Nogi/AFP Photo)

A picture made available on March 30, 2015 shows the body of Sifis, a crocodile, at the island on Crete. A man-eating crocodile that became an attraction on the Greek island of Crete last year after its mysterious appearance in a lake has died, probably of cold, an official said. Nickhamed Sifis – Cretan for Joseph – the Nile crocodile had assumed nationwide notoriety after being discovered last summer at an artificial lake. The fearsome two-metre reptile was last seen in mid-February, Mamangakis said, adding that an initial veterinary inspection had pointed to death from cold exposure. (Photo by AFP Photo/Stringer)

A pigeon dips its head in a water fountain as they take a bath in suburban Quezon city, east of Manila, Philippines on Wednesday, April 1, 2015. (Photo by Aaron Favila/AP Photo)

Sea lions lay on marina docks in Astoria, Oregon March 29, 2015. (Photo by Steve Dipaola/Reuters)

A cow is pictured on April 1, 2015 at the Dottenfelder Hof farm near Bad Vilbel, western Germany. German dairy farmers, Europe's biggest producers, will be glad to see the back of the production limits that have prevented them from exploiting the export opportunities offered by the rising middle classes in Asia. (Photo by Boris Roessler/AFP Photo)

Baboons shelter from the wind in their enclosure at Yorkshire Wildlife Park on March 31, 2015. (Photo by Lynne Cameron/PA Wire)