Deathworld by Harry Harrison

Jason dinAlit, an inhabitant of the planet Porgostrosaand, is a fast talking, conniving, tough as nails, gun toting gambler whose ethics wax and wane with each planet he travels to. He also has amazing psionic abilities which means he is gifted with a variety of psychic abilities including telekinesis, telepathy, pyrokinesis and a host of other interesting capabilities. He is not above using these to tip the odds in his favor while gambling. A chance meeting with Kerk Pyrrus who is the Ambassador of planet Pyrrus ends up with dinAlit traveling back with the Ambassador to Pyrrus. Here he discovers to his shock that everything on Pyrrus is predatory. Large creatures attack small ones, while smaller ones are armed with deadly neurotoxins. The plants are all carnivorous, while life evolves at lightning speed on the planet. In the course of his explorations of this terrible planet, dinAlit meets a strange race of humans called “grubbers” who live on the fringes of the city. The rest of the