Many animals (mammals and some birds, particularly) have been observed at play during different stages of development. Although play would seem to be random, scientists have described three patterns: 1) social, for establishing relationships with other animals; 2) exercise, for development of muscles; and 3) exploration of an object. All of these occur during the wrestling, chasing, and tumbling activities of the young of many species. Some juvenile play, such as lion cubs capturing mice, may be practice for adult activities such as hunting.