Shrew opossums are about the size of a small rat ( 9 -- 14 cm long ) , with thin limbs , a long , pointed snout and a slender , hairy tail . Shrew opossums ( also known as rat opossums or caenolestids ) are about the size of a small rat ( 9 -- 14 cm long ) , with thin limbs , a long , pointed snout and a slender , hairy tail .