In this photo provided by the Chicago Zoological Society, Thani, left, a 3-year-old white-cheeked gibbon checks out Kekasih, a 4-year-old orangutan, while exploring the Tropic World Asia exhibit at the Brookfield Zoo in Brookfield, Ill. Guests may occasionally see Thani jump from the high trees in the indoor habitat to the large peninsula to visit his new friend.