A behavior that is innate occurs without being learned. As long as we can assume that the environment is sufficient for the organism to survive, this independence from learning might lead us to look for the genes that determine the trait.
Some complications: Behaviors still have to be developed—they are not evident in the fertilized egg! Investigations of development show that behaviors that are fixed in normal circumstances can still be changed. For example, as Anne Fausto-Sterling describes, an innate behavior of rat pups is to crawl to their mother’s teats after birth. Experimental studies have shown, however, that if the mothers are fed peppermint while pregnant, the newborn rat pups crawl towards the peppermint taste even if that takes them away from their mothers. We still have to explain the development of the innate behavior of pups crawling towards a taste that is familiar, but the experiment shows us the value of not simply looking at genes when elucidating development of innate behaviors. (It also invites us to imagine changes in the environment that render changeable behaviors that we had thought were universal to the species.)
(Introduction to this series of posts)