A kind of mammal which has no canine teeth (6)
I believe the answer is:
rodent
(Other definitions for rodent that I've seen before include "Mouse, squirrel or rat" , "Eg, mouse, squirrel" , "Mouse or squirrel, say" , "Placental mammal having a single pair of incisor, 'gnawing', teeth" , "A rat, for instance" .)