 Cats have either a mutualistic or commensal relationship with humans . Two main theories are given about how cats were domesticated . In one , people deliberately tamed cats in a process of artificial selection as they were useful predators of vermin . This has been criticized as implausible , because the reward for such an effort may have been too little ; cats generally do not carry out commands and although they do eat rodents , other species such as ferrets or terriers may be better at controlling these pests . The alternative idea is that cats were simply tolerated by people and gradually diverged from their wild relatives through natural selection , as they adapted to hunting the vermin found around humans in towns and villages . 
