In the SparkNote on Signaling and Communication, we examined ways in which animals convey information to each other. In this SparkNote on Behavioral ecology we will visit a whole host of ways in which animals can interact with each other and with their environments. No animal is a solitary being. Even generally antisocial animals must at some point interact with others, and are constantly interacting with their environment. Up until now, most of our discussion of animal behavior focused on the mechanisms of animal behavior. Behavioral ecology is set more in an ultimate framework, asking how and why interactive behaviors have evolved.

First, we will examine two models describing choices animals must make while searching for food. The contingency theory states that an animal choosing between two food types must maximize the energy it will receive from the food divided by the time it takes to obtain the food. An animal will eat a more abundant, but less profitable food item only if the energy gained per unit time spent is greater than a more profitable item. The marginal value theory describes an animal's decision to leave a used up food source in search of a fresh source.

Next, we will use game theory to describe conflicts between two animals. When two animals have a conflict of interest and have two strategies to choose from, we can determine which is the best strategy or the best proportion of strategies to maximize the animal's payoff. Although game theory is only a simple model, it is useful to apply it to real-world situations in which an animal must decide which strategy to employ.

From our study of natural selection, it seems obvious thatnatural selection seems a process favoring "selfish genes," genes that maximize an individual's survival and reproductive fitness over that of its fellow species. By examining inclusive fitness, we can see how social living is also profitable for related individuals, and therefore how such communal living structuresmight have evolved.

Finally, we will take a look at sexual behavior. Sexual reproduction is not a universal strategy and so we will examine the advantages and disadvantage of this system versus asexual reproduction. We will see how sexual selection acts on populations as a specialized version of natural selection.