A polar bear swims in the sun and warm temperature around 25 degrees Celsius (77 degrees Fahrenheit) at their outdoor enclosure at Schoenbrunn zoo, in Vienna Austria, on Thursday, July 29, 2010. (AP Photo/Ronald Zak)

This undated photo provided by Annemarie Ferrie for the Turtle Back Zoo shows an otter snacking on a "fishsicle" (fish in the middle) at the Turtle Back Zoo in West Orange, N.J. (AP Photo/Turtle Back Zoo, Annemarie Ferrie)

Penguins walk in a basin of the zoological garden in Dresden, Germany, Wednesday, July 21, 2010. (AP Photo/dapd/Matthias Rietschel)

This July 28, 2006 file photo shows George, a two-and-a-half-year old lowland gorilla, as he licks his frozen treat at the Oklahoma City Zoo, in Oklahoma City. (AP Photo/Sue Ogrocki, FILE)

This undated photo provided by G. Jones for the Columbus Zoo and Aquarium shows a polar bear diving into the water at Columbus Zoo and Aquarium in Powell, Ohio. (AP Photo/G. Jones, Columbus Zoo and Aquarium)

This July 7, 2010 file photo shows Tian Tian, one of the National Zoo's pandas, checking out two fruit popsicles on a hot summer day at the zoo in Washington. (AP Photo/Jacquelyn Martin, FILE)

A grizzly bear eats a cookie treat in a viewing area Thursday, July 15, 2010, at the San Francisco Zoo in San Francisco. (AP Photo/Ben Margot)

A polar bear has a bucket on his head, while cub polar bear swims nearby in the cooling waters of Moscow Zoo, on Wednesday, July 21, 2010. (AP Photo/Misha Japaridze)

Dino, a llama at the Brandywine Zoo in Wilmington, Del. stands in front of a box fan that the zoo has mounted on the fence for him and his six other pen mates to keep cool. (AP Photo/The Wilmington News-Journal, Jennifer Corbett)

A Western Lowland Gorilla plays with a plastic bowling ball at the Brookfield Zoo Thursday, July 15, 2010 in Brookfield, Ill. (AP Photo/Charles Rex Arbogast)

A polar bear bites an ice bar containing the apples at a zoo in Osaka, western Japan Friday, July 23, 2010. (AP Photo/Kyodo News)

This June 9, 2008 file photo shows Naba, a four-year-old female African lion, as she keeps cool by licking a "bloodsicle" made of frozen cow blood, at the National Zoo in Washington. (AP Photo/Charles Dharapak, FILE)

An Indian Rhinoceros refreshing itself in a pool in the zoo in Basel, Switzerland Wednesday, July 14, 2010. (AP Photo/dapd/Winfried Rothermel)

This July 28, 2006 file photo shows Toba, a 34-year-old orangutan, as she enjoys a frozen treat at the Oklahoma City Zoo, in Oklahoma City. (AP Photo/Sue Ogrocki, FILE)

Two Spider Monkeys nap at the Brookfield Zoo Thursday, July 15, 2010 in Brookfield, Ill. (AP Photo/Charles Rex Arbogast)