How can nepotism be defined in animal behavior?

Nepotism in animal behavior refers to the preferential treatment that individuals give to their relatives in various social interactions, such as mating, foraging, and resource distribution. This behavior is often advantageous from an evolutionary perspective, as helping relatives can increase the likelihood of passing shared genes to future generations. By favoring kin, animals can enhance their inclusive fitness — a concept that encompasses not only the direct reproduction of an individual but also the indirect reproduction achieved by aiding relatives.

In many species, such behaviors can manifest in various forms, such as increased grooming, sharing food, or even more complex cooperative care of offspring. This kin-based favoritism contributes to the survival and reproductive success of related individuals, thereby reinforcing genetic ties within families and social groups.

The other options do not effectively capture the essence of nepotism as it applies to animal behavior. Altruism among unrelated individuals, competition for food, and cooperative behaviors without familial ties all depict relationships and interactions that do not prioritize familial connections, which is the core of what nepotism entails in animal social structures.