How do animal territories become economically defendable?

In biology, animal territories are considered "economically defendable" when the benefits of restricting access to a specific area outweigh the costs of defending it. This concept relies on a shifting balance between energy gains and expenditures.12

Factors Influencing Economic Defendability

• Resource Distribution: Territories are most easily managed and defended when resources are clumped together. As resources become more spread out or decline in quality, the benefits of defense decrease.1
• Resource Quality: Territoriality is generally expected when resources are of intermediate quality. If resources are too poor, they are not worth the energy to defend; if they are exceptionally high in quality, competition may become so intense that maintaining exclusive access is too costly.1
• Cost-Benefit Balance: The costs of defense—which include the energy required to patrol boundaries, advertise presence, and engage in direct combat—must be lower than the benefits gained, such as exclusive access to food, mates, or shelter.12
• Competitor Density: As the number of competitors increases, the cost of defense rises, which can shrink the optimal territory size or render it indefensible, leading animals to abandon territorial behavior altogether.12