1. A method for characterizing animal behavior, comprising: segregating images of an animal from video images of the animal in a behavioral analysis apparatus, wherein the video images are taken only from a top view; identifying at least one body part of the animal based on the images taken from a top view; identifying a center of mass of the animal based on the images taken from a top view; and characterizing behavior of the animal using the at least one body part and the center of mass of the animal.