Animals often select their habitats based on the availability of food and mates, but some species engage in migration, which is the long-distance movement of populations typically linked to seasonal changes. Migration can occur for various reasons, including food availability, climate variations, and mating opportunities. There are three primary types of migration: piloting, which involves navigating using familiar landmarks; compass orientation, where animals move in a specific direction; and true navigation, which allows animals to find their way as if they were using a map. An example of true navigation is seen in sea turtles, which can sense the Earth's magnetic field to orient themselves accurately, even when disoriented.

Another fascinating behavior in the animal kingdom is altruism, which may seem counterintuitive as it involves a fitness cost to the individual performing the act, while the recipient benefits. This behavior can be explained through kin selection, an evolutionary strategy that enhances the reproductive success of an organism's relatives. Hamilton's rule provides a framework for understanding altruism, stating that altruistic behavior is more likely when the benefit to the recipient is high, the cost to the actor is low, and the coefficient of relatedness—representing the shared genetic material between individuals—is significant. This relationship can be expressed with the equation:

Benefit to recipient × Coefficient of relatedness > Cost to actor

Inclusive fitness expands the concept of fitness by considering not only the number of offspring an organism produces but also how it aids relatives in producing more offspring. This perspective suggests that altruistic behaviors, while not directly spreading an individual's genes, can still contribute to the propagation of shared genetic material among relatives.

Reciprocal altruism is another intriguing concept, occurring between unrelated individuals. In this scenario, an individual may temporarily lower its fitness to benefit another, with the expectation of future reciprocation. This behavior is observed in chimpanzee communities and may also shed light on human altruism.

A notable example of altruism is found in prairie dogs, which live in large communities with many relatives. When they detect a predator, they emit alarm calls to warn others, even though this behavior increases their own risk of predation. By alerting their community, prairie dogs enhance the survival chances of their relatives, thereby contributing to their inclusive fitness.