(AP) - Zoo Cain, foreground, attends a crowded caucus in Portland, Maine, Saturday, Feb. 11, 2012. (AP Photo/Robert F. Bukaty)

(AP) - Zoo Cain, right, listens to Republican presidential candidate Mitt Romney speaks at a caucus, Saturday, Feb. 11, 2012, in Portland, Maine. (AP Photo/Robert F. Bukaty)

(AP) - Panda Er Shun eats bamboo at the Panda House at the Chongqing Zoo in Chongqing, China, Saturday, Feb. 11, 2012. Two giant pandas including Er Shun will call Canada home for the next 10 years. (AP Photo/The Canadian Press, Adrian Wyld)

(AP) - Panda Er Shun eats bamboo at the Panda House at the Chongqing Zoo in Chongqing, China, Saturday, Feb. 11, 2012. Two giant pandas including Er Shun will call Canada home for the next 10 years. (AP Photo/The Canadian Press, Adrian Wyld)

(Reuters) - Canada's Prime Minister Stephen Harper pets a panda with his wife Laureen at a zoo in Chongqing February 11, 2012. REUTERS/Chris Wattie (CHINA - Tags: POLITICS ANIMALS)

(Reuters) - Giant panda Er Shun is pictured at the zoo in Chongqing February 11, 2012. Canada's Prime Minister Stephen Harper announced two giant pandas, Er Shun and Ji Li, will spend 10 years in two Canadian zoos. REUTERS/Chris Wattie (CHINA - Tags: POLITICS ANIMALS)

(Reuters) - Canada's Prime Minister Stephen Harper looks at a panda being held by his wife Laureen at a zoo in Chongqing February 11, 2012. Harper announced that two giant pandas, Er Shun and Ji Li (both not pictured), will spend 10 years in two Canadian zoos. REUTERS/Chris Wattie (CHINA - Tags: ANIMALS POLITICS ENTERTAINMENT)

(Reuters) - Canada's Prime Minister Stephen Harper speaks at the zoo in Chongqing February 11, 2012. Harper announced that two giant pandas, Er Shun and Ji Li, will spend 10 years in two Canadian zoos. REUTERS/Chris Wattie (CHINA - Tags: ANIMALS POLITICS)

(Reuters) - Canada's Prime Minister Stephen Harper looks back at giant panda Er Shun while speaking at the zoo in Chongqing February 11, 2012. Harper announced two giant pandas, Er Shun and Ji Li, will spend 10 years in two Canadian zoos. REUTERS/Chris Wattie (CHINA - Tags: POLITICS ANIMALS)

(Reuters) - Canada's Prime Minister Stephen Harper reacts while petting a panda held by his wife Laureen at a zoo in Chongqing February 11, 2012. REUTERS/Chris Wattie (CHINA - Tags: POLITICS ANIMALS)

(AP) - Canadian Prime Minister Stephen Harper speaks while visiting the Panda House at the Chongqing Zoo in Chongqing, China Saturday Saturday Feb. 11, 2012. Two giant pandas will call Canada home for the next 10 years. (AP Photo/The Canadian Press, Adrian Wyld)

(AP) - Panda Er Shun eats bamboo at the Panda House at the Chongqing Zoo in Chongqing, China Saturday Feb. 11, 2012. Two giant pandas including Er Shun will call Canada home for the next 10 years. (AP Photo/The Canadian Press, Adrian Wyld)

(AP) - Canadian Prime Minister Stephen Harper looks on as his wife Laureen holds a panda in Chongqing, China on Saturday Feb. 11, 2012. Two giant pandas will call Canada home for the next 10 years. It is expected that the giant pandas will arrive at the Toronto zoo in early 2013. (AP Photo/The Canadian Press, Adrian Wyld)

(AP) - Bear 'Ze Colmeia' cools off from the intense summer heat with frozen grapes at Rio de Janeiro's city zoo, Thursday, Feb. 9, 2012. (AP Photo/Silvia Izquierdo)

(AP) - Tiger 'Neto' cools off from the intense summer heat inside a swimming pool at the city zoo in Rio de Janeiro, Brazil, Thursday, Feb. 9, 2012. (AP Photo/Silvia Izquierdo)

(AP) - Chimpanzee 'Paulinho' cools off from the intense summer heat with a watermellon juice at the city zoo in Rio de Janeiro, Brazil, Thursday, Feb. 9, 2012. (AP Photo/Silvia Izquierdo)

(AP) - Tiger 'Neto' cools off from the intense summer heat inside a swimming pool at the city zoo in Rio de Janeiro, Brazil, Thursday, Feb. 9, 2012. (AP Photo/Silvia Izquierdo)

(AP) - Oranguntan 'Tanguinha' cools off from the intense summer heat with a manga ice cream at Rio de Janeiro's city zoo, Thursday, Feb. 9, 2012. (AP Photo/Silvia Izquierdo)

(Reuters) - A pig-tailed macaque is warmed by an electric heater at the Sofia city zoo February 9, 2012. Temperatures in Bulgaria fell to as low as minus 28 degrees Celsius (minus 18.4 degrees Fahrenheit) on Thursday following the heavy snowfall earlier this week that caused traffic havoc across the country. REUTERS/Stoyan Nenov (BULGARIA - Tags: ENVIRONMENT SOCIETY ANIMALS)

(Reuters) - An 18-month-old Siberian tiger plays in the winter snow at Skopje ZOO February 7, 2012. REUTERS/Ognen Teofilovski (MACEDONIA - Tags: ANIMALS ENVIRONMENT)

(Reuters) - An 18-month-old Siberian tiger plays in the winter snow at Skopje ZOO February 7, 2012. REUTERS/Ognen Teofilovski (MACEDONIA - Tags: ANIMALS ENVIRONMENT)

(Reuters) - A goose rests on the winter snow at Skopje ZOO February 7, 2012. REUTERS/Ognen Teofilovski (MACEDONIA - Tags: ANIMALS ENVIRONMENT)

(Reuters) - Siberian tigers play in the winter snow at Skopje ZOO February 7, 2012. REUTERS/Ognen Teofilovski (MACEDONIA - Tags: ANIMALS ENVIRONMENT)

(Reuters) - An 18-month-old Siberian tiger plays in the winter snow at Skopje ZOO February 7, 2012. REUTERS/Ognen Teofilovski (MACEDONIA - Tags: ANIMALS ENVIRONMENT)

(Reuters) - Ducks sits in the frozen water in the zoo in the Serbian capital Belgrade February 7, 2012. REUTERS/Marko Djurica (SERBIA - Tags: ANIMALS ENVIRONMENT)

(Reuters) - White lions play in the snow in the zoo in the Serbian capital Belgrade February 7, 2012. Zookeepers said it was highly unusual for lions to emerge from their cages and play in the winter snow, which has otherwise caused chaos in the Balkan country and across Europe. REUTERS/Marko Djurica (SERBIA - Tags: ANIMALS ENVIRONMENT)

(Reuters) - A white lion plays in the snow in the zoo in the Serbian capital Belgrade February 7, 2012. Zookeepers said it was highly unusual for lions to emerge from their cages and play in the winter snow, which has otherwise caused chaos in the Balkan country and across Europe. REUTERS/Marko Djurica (SERBIA - Tags: ANIMALS ENVIRONMENT)

(Reuters) - White lions play in the snow in the zoo in the Serbian capital Belgrade February 7, 2012. Zookeepers said it was highly unusual for lions to emerge from their cages and play in the winter snow, which has otherwise caused chaos in the Balkan country and across Europe. REUTERS/Marko Djurica (SERBIA - Tags: ANIMALS ENVIRONMENT)

(Reuters) - A lion (R) plays with white lions in the snow in the zoo in the Serbian capital Belgrade February 7, 2012. Zookeepers said it was highly unusual for lions to emerge from their cages and play in the winter snow, which has otherwise caused chaos in the Balkan country and across Europe. REUTERS/Marko Djurica (SERBIA - Tags: ANIMALS ENVIRONMENT)

(Reuters) - White lions play in the snow in the zoo in the Serbian capital Belgrade February 7, 2012. Zookeepers said it was highly unusual for lions to emerge from their cages and play in the winter snow, which has otherwise caused chaos in the Balkan country and across Europe. REUTERS/Marko Djurica (SERBIA - Tags: ANIMALS ENVIRONMENT)

(Reuters) - Veterinary staff tend to Juba the cheetah cub following his operation at Chester Zoo, northern England, February 3, 2012. The 9 month old cat was undergoing surgery to insert a metal plate in his right ankle to mend a fracture. Picture taken February 3, 2012. REUTERS/Phil Noble (BRITAIN - Tags: ENVIRONMENT SOCIETY ANIMALS)

(Reuters) - Consultant orthopaedic surgeon Rob Pettit secures a metal plate in the leg of Juba the cheetah during an operation at Chester Zoo, northern England, February 3, 2012. The 9 month old cat was undergoing surgery to insert a metal plate in his right ankle to mend a fracture. Picture taken February 3, 2012. REUTERS/Phil Noble (BRITAIN - Tags: ANIMALS ENVIRONMENT SOCIETY)

(Reuters) - Consultant orthopaedic surgeon Rob Pettit secures a metal plate in the leg of Juba the cheetah during an operation at Chester Zoo, northern England, February 3, 2012. The 9 month old cat was undergoing surgery to insert a metal plate in his right ankle to mend a fracture. Picture taken February 3, 2012. REUTERS/Phil Noble (BRITAIN - Tags: ENVIRONMENT SOCIETY ANIMALS)

(Reuters) - Veterinary staff lift Juba the cheetah cub onto a set of scales ahead of his operation at Chester Zoo, northern England, February 3, 2012. The 9 month old cat was undergoing surgery to insert a metal plate in his right ankle to mend a fracture. Picture taken February 3, 2012. REUTERS/Phil Noble (BRITAIN - Tags: ENVIRONMENT SOCIETY ANIMALS)

(Reuters) - Senior veterinary nurse Ali Kelsall washes the shaved leg of Juba the cheetah cub ahead of his operation at Chester Zoo, northern England, February 3, 2012. The 9 month old cat was undergoing surgery to insert a metal plate in his right ankle to mend a fracture. Picture taken February 3, 2012. REUTERS/Phil Noble (BRITAIN - Tags: ENVIRONMENT SOCIETY ANIMALS)

(Reuters) - Veterinary staff tend to Juba the Cheetah cub following his operation at Chester Zoo, northern England, February 3, 2012. The 9 month old cat was undergoing surgery to insert a metal plate in his right ankle to mend a fracture. Picture taken February 3, 2012. REUTERS/Phil Noble (BRITAIN - Tags: ENVIRONMENT SOCIETY ANIMALS)

(Reuters) - Veterinary staff tend to Juba the cheetah cub following his operation at Chester Zoo, northern England, February 3, 2012. The 9 month old cat was undergoing surgery to insert a metal plate in his right ankle to mend a fracture. Picture taken February 3, 2012. REUTERS/Phil Noble (BRITAIN - Tags: ENVIRONMENT SOCIETY ANIMALS)

(Reuters) - Veterinary staff prepare Juba the cheetah cub for his operation at Chester Zoo, northern England, February 3, 2012. The 9 month old cat was undergoing surgery to insert a metal plate in his right ankle to mend a fracture. Picture taken February 3, 2012. REUTERS/Phil Noble (BRITAIN - Tags: ENVIRONMENT SOCIETY ANIMALS)

(Reuters) - Veterinary staff tend to Juba the cheetah cub following his operation at Chester Zoo, northern England, February 3, 2012. The 9 month old cat was undergoing surgery to insert a metal plate in his right ankle to mend a fracture. Picture taken February 3, 2012. REUTERS/Phil Noble (BRITAIN - Tags: ENVIRONMENT SOCIETY ANIMALS TPX IMAGES OF THE DAY)

(Reuters) - Senior veterinary nurse Ali Kelsall shaves the leg of Juba the cheetah cub ahead of his operation at Chester Zoo, northern England, February 3, 2012. The 9 month old cat was undergoing surgery to insert a metal plate in his right ankle to mend a fracture. Picture taken February 3, 2012. REUTERS/Phil Noble (BRITAIN - Tags: ENVIRONMENT SOCIETY ANIMALS)

(Reuters) - Veterinary staff Livia Benato (L) and Ali Kelsall (R) shave the leg of Juba the cheetah cub ahead of his operation at Chester Zoo, northern England, February 3, 2012. The 9 month old cat was undergoing surgery to insert a metal plate in his right ankle to mend a fracture. Picture taken February 3, 2012. REUTERS/Phil Noble (BRITAIN - Tags: ENVIRONMENT SOCIETY ANIMALS)

(Reuters) - Veterinary staff Tanya Grubb (L) and Livia Benato (R) tend to Juba the cheetah cub ahead of his operation at Chester Zoo, northern England, February 3, 2012. The 9 month old cat was undergoing surgery to insert a metal plate in his right ankle to mend a fracture. Picture taken February 3, 2012. REUTERS/Phil Noble (BRITAIN - Tags: ENVIRONMENT SOCIETY ANIMALS)

(Reuters) - Senior veterinary nurse Ali Kelsall washes the shaved leg of Juba the cheetah cub ahead of his operation at Chester Zoo, northern England, February 3, 2012. The 9 month old cat was undergoing surgery to insert a metal plate in his right ankle to mend a fracture. Picture taken February 3, 2012. REUTERS/Phil Noble (BRITAIN - Tags: ENVIRONMENT SOCIETY ANIMALS)

(Reuters) - An X-ray shows the repair to the leg of Juba the Cheetah cub following his operation at Chester Zoo, northern England, February 3, 2012. The 9 month old cat was undergoing surgery to insert a metal plate in his right ankle to mend a fracture. REUTERS/Phil Noble (BRITAIN - Tags: ENVIRONMENT SOCIETY ANIMALS)

(Reuters) - Carnivore keeper Andy Wolfenden carries Juba the Cheetah cub into the operating theatre after being anaesthetized ahead of his operation at Chester Zoo, northern England February 3, 2012. The 9 month old cat was undergoing surgery to insert a metal plate in his right ankle to mend a fracture. Picture taken February 3, 2012. Picture taken February 3, 2012. REUTERS/Phil Noble (BRITAIN - Tags: ENVIRONMENT SOCIETY ANIMALS)

(Reuters) - Veterinary staff lift Juba the Cheetah cub onto a set of scales ahead of his operation at Chester Zoo, northern England, February 3, 2012. The 9 month old cat was undergoing surgery to insert a metal plate in his right ankle to mend a fracture. Picture taken February 3, 2012. REUTERS/Phil Noble (BRITAIN - Tags: ENVIRONMENT SOCIETY ANIMALS)

(AP) - CORRECTS PHOTOGRAPHER BYLINE - A bear sits as young bears play in a snow covered zoo in Ankara, Turkey, on Saturday, Feb. 4, 2012. Turkey has been hit by a cold snap that has blanketed much of the country in snow. (AP Photo/ Uzay Hacaoglu)

(AP) - CORRECTS PHOTOGRAPHER BYLINE - A bear sits as young bears play in a snow covered zoo in Ankara, Turkey, on Saturday, Feb. 4, 2012. Turkey has been hit by a cold snap that has blanketed much of the country in snow. (AP Photo/ Uzay Hacaoglu)

(AP) - A mother and her son poses for a picture before the jaw of a mock shark at a snow covered zoo in Ankara, Turkey, on Saturday, Feb. 4, 2012. Turkey has been hit by a cold snap that has blanketed much of the country in snow. (AP Photo/Selcan Hacaoglu)

(AP) - A young bear plays with a tire at a snow covered zoo in Ankara, Turkey, on Saturday, Feb. 4, 2012. Turkey has been hit by a cold snap that has blanketed much of the country in snow. (AP Photo/Selcan Hacaoglu)