The Rex is a rough coated guinea pig. The coat has no guard hairs, which gives it a woolly texture. The coat is dense, and the hairs are no longer than 1cm, and stands directly out from the body, giving it a hedgehog-like appearance. The Rex has a broad head and large droopy ears. The underbelly is dense and curly. Rexes are bred in most colours, but the agouti colour is most popular.