The Green World — Hal Clement

Four scientists, one guide -- and a dangerous beast following their trail. Nothing unusual from the looks of things, except that they are all in a planet far away from Earth.
Robin Lampert, Take Mitsuitei, Hans Krendall and Ndomi Sulewayo, and their guide John McLaughlin, get together to scour the wilds of Viridis and take what scientific information the land can offer. They discover puzzling yet wondrous mysteries, yet little do they know that the the land itself is unwilling to give them the answers.