Behaviors have costs and benefits

A cost–benefit approach can be used to investigate the relationships between behavior, environment, and fitness. A cost–benefit approach assumes that an animal has only a limited amount of time and energy, and therefore cannot afford to engage in behaviors that cost more to perform than they return in benefits. A cost–benefit approach provides a framework that can be used to construct hypotheses and design experiments to investigate why behavior patterns evolve as they do.

The benefits of a behavior are measured in terms of the enhancement in fitness an animal accrues by performing the behavior. The cost of a behavior typically has three components:

  1. Energetic cost is the energy the animal expends performing the behavior.

  2. Risk cost is the increased chance of being injured or killed.

  3. Opportunity cost is the benefit the animal forgoes by not being able to perform other behaviors at the same time.