Animal locomotion many of these same principles may be applied to climbing without trees, such as on rock piles or mountains. The earliest known tetrapod with specializations that adapted it for climbing trees, was "Suminia", a synapsid of the late Permian, about 260 million years ago. Some invertebrate animals are exclusively arboreal in habitat, for example, the tree snail. "Brachiation" (from "brachium", Latin for "arm"), is a form of arboreal locomotion in which primates swing from tree limb to tree limb using only their arms. During brachiation, the body is alternately supported under each forelimb. This is the primary means of locomotion
Prostitution among animals observed. A study at Yale–New Haven Hospital trains capuchin monkeys to use silver discs as money in order to study their economic behavior. The discs could be exchanged by the monkeys for various treats. During one chaotic incident, a researcher observed what appeared to be a monkey exchanging a disc for sex. The monkey that was paid for sex immediately traded the silver disc for a grape. The researcher took steps to prevent any possibility of coins being traded for sex after his suspicions were aroused. Prostitution among animals A few studies have suggested that prostitution exists among different species