Regardless of the interaction being voluntary or involuntary, almost every organism can be seen engaging in some form of social behavior. Social behaviors are adaptive in order to promote survivability and reproductive success. The most common social behavior is communication. In animals, most communication can be grouped as non-verbal. However, humans display both verbal and non-verbal communications. Communication between two or more individuals involves the production of the communication signals, its reception, and interpretation. Communication in organisms can be predominately divided into visual, auditory, chemical, and tactile communication. Apart from these categories of social modalities, some animals also utilize seismic, thermal, and electrocommunication. Different organisms rely on different modes of communication and their combinations.
Further classification of social behavior can be based on the type of interaction. When an interaction results in the benefit of all interacting parties, then it is a mutualistic behavior. Such interactions can also be seen between members of two different species. Altruistic interactions, on the other hand, results in the benefit of only the recipient, such as warning calls in birds. While these behaviors tend to be detrimental to the survival of the altruist, in some cases, the decision to indulge in these behaviors is calculated risk. Animals may engage in altruistic behaviors with the hope of future reciprocation. A common example of this is the reciprocal altruistic food sharing behavior among roost-mates that has been observed in vampire bats (Denault & McFarlane, 1995). However, not all social interactions are positive in nature. Animals can partake in both selfish and spiteful behaviors, with the latter behavior resulting in all interacting parties suffering the cost.
Highly social animals can be seen living in close-knit groups and engaging in behaviors that contribute to the maintenance of the group. Based on the degree of social interactions and cooperative living (excluding mating behaviors), animal sociality can be divided into isolatory, parasocial, and eusocial. Isolatory animals usually only partake in caring for their young (sub-social). In some cases, isolatory animals may occasionally cohabitate with other adults and young ones (solitary but social). Parasociality, on the other hand, is characterized by cooperative dwelling. Based on the responsibilities undertaken by the group members, para-sociality is further divided into communal, quasi-social, and semi-social communities. Communal animals care for their own offspring, while quasi-social animals share parental responsibilities in the nest. On the other hand, semi-social organisms not only share brood care responsibilities but also have a biological caste system in place. In addition to encompassing characteristics of semi-social organisms, eusocial societies have overlapping adult generations, cooperative care of young, and division of reproductive labor.
Social behaviors are influenced by a range of intrinsic and external factors in organisms. Studies of social behavior allow understanding of issues associated with animal conservation and wellbeing. Apart from understanding animal-centric issues and processes, animal social behavior also allows the generation of ideas that can be applied for betterment and development of human societies. Animal models are often used to understand and develop treatments for neuropsychiatric disorders and diseases that impact sociability in humans. Additionally, animal social behaviors also provide insights into the causes and evolution of human behaviors and the ideas that influence them.