A primatologist's study is the scientific study of primates, which are a group of mammals that includes humans, APES, monkeys, and other related species. Primatologists study the behavior, ecology, and evolution of these animals in order to gain insight into human behavior. The two crossword solutions for the term PRIMATOLOGIST'S STUDY are APES (4 letters) and APE (3 letters). APES refers to the family of primates that includes gorillas, chimpanzees, orangutans, and gibbons, while APE is a more general term that can refer to any primate species.