sociability

(group cohesion, group bonds), in animal behavior, a property of some animals to form aggregates, such as flocks, herds, shoals, or colonies; it is associated with specific behavioral reactions.

Sociability is an adaptation to environmental conditions. The formation of groups is associated with the search for food (pelicans), protection agaist enemies (ungulates), mutual heating (lower primates), and mutual rearing of the young (some insects). Aggregates of animals may be temporary (for breeding, hibernation, or migration) or permanent.

Among invertebrates, sociability is most often encountered in insects. Its simplest form is the formation of aggregates of larvae: the females deposit their eggs in a common place that has an abundant food supply. Such aggregates are formed, for example, by many grasshoppers and processionary moths. After exhausting the food supply of a particular location, groups of insects may make distant migrations (locusts, processionary moths). A more complex form of sociability is the formation by some insects (honeybees, ants, termites, wasps) of permanent colonies, usually characterized by the division of labor among individuals and by polymorphism.

The simplest type of sociability among vertebrates is the formation of schools of fish for long feeding or spawning migrations. More complex is the formation of nesting colonies by many birds, including seagulls, penguins, and sociable weaver-birds. In the autumn, birds of temperate and cold latitudes form flocks for feeding migrations. Among mammals, aggregates are formed by pinnipeds (seal rookeries), many ungulates, and some rodents.

Certain instincts form the basis of animal sociability. Among lower primates, the herd behavior of sacred baboons is made possible by complex sonic signaling, including congenital vocal reflexes that are specific for a given physiological state. In ungulates, visual and olfactory analyzers are important in herd behavior. Visual analyzers, for example, enable an animal to react to a herd that is moving away. The odor of secretions from the scent glands present in most ungulates makes it possible for an animal to find other individuals of its species. It is characteristic that sociability is most often exhibited in mammals that live in open spaces, thus facilitating perception of signals from other individuals of one’s own species (see).

Besides herd reactions, an important role in the behavior of social animals is played by mimetic reflexes, which may be unconditioned (congenital) or conditioned, that is, formed in response to visual or auditory stimuli. The migrations of schools of fish and flocks of birds are based on unconditioned mimetic reflexes. Certain animals, such as some bats, rodents, and ungulates, when gathering into herds or colonies, exhibit a significant decrease in metabolic intensity. This permits the animals to tolerate better a deficiency of food.

The term “sociability,” although widely accepted among animal behaviorists, is inappropriate because it suggests an anthropomorphic evaluation of animal behavior.