What is "speaker-to-animals"

Speaker-to-Animals (or later Chmeee) is a fictional character in the Ringworld series of books, written by Larry Niven.

In Ringworld, Speaker-to-Animals is a junior diplomat who is trained to deal with other species without reflexively killing them. He is recruited by Nessus, a Pierson's Puppeteer, as a member of an expedition to explore the Ringworld.