 Primatologists like Cheney and Seyfarth, psychologists like Tomasello, anthropologists like Terrence Deacon, and linguists like Phillip Lieberman share an interest in investigating the communicative, anatomical, and cognitive characteristics of non-human animals to identify biological differences between humans, and monkeys and primates. In the following paragraph we discuss Cheney and Seyfarth (2005) as an example, but we could easily have chosen any of a number of other theorists.