Ethology is a noun that refers to the study of animal behavior. 

The Greek word ethos (EE thoss) refers to ‘nature’ or ‘disposition’ and the common suffix O-L-O-G-Y means ‘study of.’ When combined, we get a word that refers to the study of the nature of animals. Examples:

I have to whistle and scream my brains out to get our bulldog Sparky to come in from the yard at the end of the day. But somehow, my daughter only needs to lift a finger to get him in. One of these days that girl’s knowledge of animals is going to make her a fortune in ethology.