A herpetologist is a person who studies reptiles and amphibians (including turtles).
The specific term for someone who studies turtles is testudinologist. A more general term that includes terrapins and tortoises is cheloniologist. Both words return many hundreds of hits on Google.
You could also say the Queen of Hearts piqued Alice's interest in psuedotestudinology though you are unlikely to find many hits for the word on Google.
A person who studies crocodiles is called a herpetologist.
A person who studies genealogies is a genealogist.
A person who studies philosophy is called a philosopher.
A person who studies organisms is called a biologist.
a person who studies people but not an psychologist
a person that studies gems is called a gemologist.
what do you call somebody who studies snails.
A person who studies birds is called an ornithologist.
A person who studies birds is called an Ornitholoigst
A person who studies poisons is called a toxicologist.
A person who studies lichens is called a lichenologist.
A person who studies theology is called a theologian.