Animals at the Zoo (51 images)

Four red river piglets, born on April 27, 2008, root around their father, Legolas, at the San Diego Zoo on June 18, 2008. The piglets get their striped and spotted look from a combination of dark skin beneath light hair. This coloring helps young red river hogs blend into their native rain forest habitat in central and western Africa. These wild pigs get their name from their behavior of wallowing in ponds and streams and the color of their hair. (UPI Photo/Ken Bohn/San Diego Zoo)

Carol Fieseler, a quarantine specialist gives Sofiya, a new born Amur leopard,a bottle during a feeding in the Childrens Zoo in St. Louis on June 12, 2008. The endangered female was born on May 10. Bottle feeding will continue for three months. The Amur Leopard is considered one of the most endangered cat subspecies in the world with only approximately 40 left in the wild forests of the Primorye Province of Eastern Russia. (UPI Photo/Bill Greenblatt)

A 7-year-old polar bear named Kalluk plays with a burlap doll painted with non-toxic paint by zookeepers at the San Diego Zoo on May 8, 2008. The paint left the blue-green shade seen on the bear's fur. (UPI Photo/Ken Bohn/San Diego Zoo)

A female trumpeter swan nuzzles her newly hatched cygnet that just emerged from the shell at Lincoln Park Zoo in Chicago on May 29, 2008. This cygnet is slated to be released to the wild this fall as part of swan re-introduction and recovery program. Trumpeter swans were hunted to near extinction in 1900 and now, thanks to managed breeding and recovery efforts, these swans are thriving again in many parts of the Midwest. (UPI Photo/Greg Neise/Lincoln Park Zoo)