1) Primatology 2) Zoology 1) Zoological science 2) Zoology 
In zoology, mammalogy is the study of mammals – a class of vertebrates with characteristics such as homeothermic metabolism, fur, four-chambered hearts, and complex nervous systems. Mammalogy has also been known as `mastology,` `theriology,` and `therology.` There are about 4,200 different species of animals which are considered mammals. T...
study of mammals
• (n.) The science which relates to mammals or the Mammalia. See Mammalia.
scientific study of mammals. Interest in nonhuman mammals dates far back in prehistory, and the modern science of mammalogy has its broad foundation ...
Mam·mal'o·gy noun [ Mamma breast + -logy : confer f. mammalogie .] The science which relates to mammals or the Mammalia. See Mammalia . 
[n] - the branch of zoology that studies mammals
noun the branch of zoology that studies mammals