Locomotor Play in Animals
With some notable exceptions (e.g., pinnipeds and bats), running is critical to the survival of most mammals. Running is the primary way in which most prey species (such as many rodents and ungulates) escape predators, and many carnivores (such as felids and canids) capture prey. Depending on the species, running can be important in other contexts, including agonistic encounters, mating, and the defense of one's young. Selection pressures for running abilities in some species have been so strong that some of the fastest animals on earth are large carnivores such as the cheetah, along with some of the ungulate species on which they feed.
Researchers have differentiated between two major types of locomotor play in animals: solitary locomotor-rotational play, in which young animals engage in active locomotor behavior such as running, jumping, and kicking on their own; and chasing play, in which animals engage in short or extended chases with one other. Although chasing play is sometimes combined with play-fighting to make up the category of social play in some studies of animals (and the category of rough-and-tumble play with children), it is considered separately from play-fighting in the present text because of numerous differences between the nature of social interaction in these two contexts.
The observation of locomotor play shows that it has many of the locomotor components of prey avoidance and prey capture ( Aldis, 1975) but, as was the case for play-fighting, these elements are varied in their structure. For the 60 species considered for this volume, most species that engage in play-fighting also engage in chasing play. The young of these species often engage in solitary locomotor-rotational play as well, although such behavior appears to be particularly common in some ungulate, rodent, and primate species. Very few species appear to engage in locomotor play but not play-fighting. Some bird species also engage in locomotor play, but given differences between locomotor behavior in terrestrial versus airborne species, only locomotor play in mammals is considered here.