Panamanian golden frog, Puerto Rican crested toad, and Wyoming toad. In 2002, the Zoo was awarded the AZA National Exhibit Award for Amphibiville. The Arctic Ring of Life The 4-acre Arctic Ring of Life, opened in October 2001, is home to three polar bears and two southern sea otters. It is among the largest polar bear habitats in North American zoos. In 2003, the Zoo was awarded the AZA Significant Achievement Award for the Arctic Ring of Life. Cotton Family Wetlands and Boardwalk Mimicking a Michigan ecosystem, the 1.7-acre pond and wetlands area and accompanying 7,200-square-foot boardwalk is home to native fish, frogs, turtles and birds as well as trumpeter swans. The boardwalk is made from 95-percent recycled material composed primarily of plastic grocery bags and reclaimed hardwood. The Wetlands and Boardwalk are bounded by Amphibiville, the Warchol Beaver Habitat, the Edward Mardigian Sr. River Otter Habitat, and the Holden Reptile Conservation Center. Due to a $102,350 grant from NOAA, the Wetlands are also used as professional development and outdoor classroom for teachers and students underrepresented in science fields. Cotton Family Wolf Wilderness The Cotton Family Wolf Wilderness is a $1.4 million two-acre sanctuary that features native meadows and trees, a flowing stream and pond, dens, and elevated rock outcroppings, for two gray wolves. The habitat also incorporates a renovated historic log cabin which had existed on the property. Giraffe Encounter The guests feed reticulated giraffes from an 18-foot-tall platform that extends into their habitat in the Giraffe Encounter. This experience, which started in July 2007, runs Tuesday through Sunday from spring through fall. This is an added fee. The Great Apes of Harambee The Great Apes of Harambee is a 4-acre indoor/outdoor habitat home to chimpanzees and western lowland gorillas. The animals may be rotated into each other's habitat spaces, simulating nomadic movement similar to wild behavior. Holden Reptile Conservation Center Opened as the Holden Museum of Living Reptiles in 1960, the Holden Reptile Conservation Center is home to 150 reptiles representing 70 species, 45 percent of which are considered threatened or endangered in the wild. Edward Mardigian Sr. River Otter Habitat The Edward Mardigian Sr. River Otter Habitat provides a habitat for North American river otters and features a 9,000-gallon pool with a waterfall and waterslide. The pool is enclosed on one side by a glass wall, on the other side of which is an observation building. The