The PrehistoricPulp Blog says:
Usually roleplaying games let you play as humans fighting dinosaurs. Tooth & Claw is the only one I know that lets people play as dinosaurs.
Tooth & Claw is nothing fancy. It's simply a set of rules for creating dinosaur characters and roleplaying them. There are no illustrations and it lacks flashy page design, having been cranked out on a word processor. The author writes that originally the game was to be published by a game company in 2001, but that never happened. The version he ultimately released was written in a single night so he could enter it into a gaming competition, where it won third place.
It's not a bad effort if you're looking for a rules-lite RPG. Tooth & Claw leaves it up to players to decide how realistic they want to make the game. If they want their dinosaurs to talk, no problem. If they want their dinosaurs to communicate only through grunts and body language, no problem. The rules themselves just give some basics for building dinosaurs with tail spikes, or horns, or enlarged toe claws, or pointy teeth. You could use the rules to build a Triceratops, or make up something completely new and not in the fossil record.
The game uses a dice-pool system in which players role a certain number of six-sided dice and try to get as many in sequence as possible, starting with 1. So, for example, say you role four dice and get 1, 2, 4, 5. You have two successes because 1 and 2 are in sequence. The 4 and 5 don't count because you must start with 1. The more successes you have, the more likely you are to accomplish a task or win a challenge. Positive traits let you role larger numbers of dice or let you start sequences with higher numbers than 1.
Most players will probably welcome the simplicity. Hard-core gamers who thrive on statistic complexity and ultra-realism will hate it. Tooth & Claw is a nice, easy game if you have a few dinosaur nuts at your house and you're looking for something other to do than play Monopoly. Plus it's only a $3 download at RPGnow, so it's hardly going to bankrupt you if you don't like it.