Territoriality

Territoriality is a foundational concept in animal behavior and behavioral ecology. Territoriality is commonly defined as “the defense of an area,” wherein the area being defended is known as the “territory.” Territoriality serves as a framework that allows animal behaviorists and behavioral ecologists to describe and hypothesize links among diverse aspects of animals’ biology. The many facets and functions of territoriality include the acquisition of food, nest sites, and shelter, space-use and movement behavior, and interactions with mates and competitors. Thus, because territoriality encompasses behaviors that directly determine individuals’ survival and reproduction (i.e., their fitness), it offers a powerful approach to understanding the evolution of animal behavior. Territoriality has been used to describe animal behavior for many centuries, particularly in avian systems; conversely, many advances in how biologists conceive of and use territoriality have arisen in research on birds. Operational definitions of territory fall broadly into two categories—those that focus on animals’ behavior and those that focus on their ecological relationships. That said, the question of how to conceive of territory has long been a subject of contention, with widely varied opinions on how the term should be defined and whether and how it is useful for understanding animal behavior. Discussions and critiques of territoriality, from not only animal behavior and behavioral ecology but also from the social sciences, help to contextualize and sharpen how we use the concept to understand the evolution of animal behavior. Technological and statistical advances continue to change the ways in which territories are mapped and quantified, with different methods available for taxa of different sizes, habitats, and life histories. Research on territoriality can be divided into two large domains based on the function served by territory—foraging and mating—but these two functions are intimately linked through the socioecological hypothesis that proposes a relationship between resource distributions and mating systems. This hypothesis has served to structure much research on territoriality in the last half-century or so. Finally, territoriality is pertinent not just to within-species interactions but also to between-species interactions and species coexistence, with implications for macroecological and macroevolutionary patterns and processes.