A person who studies mice is typically called a "mammalogist," as they are a type of mammal. More specifically, if their focus is on the Biology, behavior, or genetics of mice, they may also be referred to as a "rodentologist." Additionally, researchers in fields like genetics or neuroscience who work with mice as model organisms may simply be called "researchers" or "scientists" in their specific fields.
A person who studies birds is called an Ornitholoigst
A person who studies animal life is called a zoologist.
Maybe a MythBuster?:):)
a zooligyts
see: http://en.wikipedia.org/wiki/Felinology
a person who studies people but not an psychologist
A person who studies genealogies is a genealogist.
A person who studies organisms is called a biologist.
a person that studies gems is called a gemologist.
what do you call somebody who studies snails.
A person who studies poisons is called a toxicologist.
A person who studies the earth is called a geologist.
A person who studies birds is called an ornithologist.
A person who studies the mind is called a psychologist.
A person who studies birds is called an Ornitholoigst
A person who studies lichens is called a lichenologist.
A person who studies theology is called a theologian.