Rabbits & Large Rodents
Last Review/Updated: May 31, 2002
Rabbits and large rodents are gnawing mammals, specialized for eating vegetation. Although the two groups are similar in form and life style, they differ in body structure and have separate evolutionary histories.
Rodents are the largest group of mammals (Order Rodentia), comprising over 1600 species world-wide. In Alberta, there are 37 species of rodents. Only larger rodents are presented here.
Rodents have a single pair of large incisor (front) teeth on each jaw. These teeth are separated from the grinding (cheek) teeth by a large space. Rodents do not have canine (eye) teeth. Unlike other teeth, the incisors of rodents continue to grow throughout their lives. Therefore, each rodent must continually gnaw to keep these teeth worn down to their proper length. The outer surface of each incisor tooth is composed of enamel which is harder than the soft dentine of the inner surface. The dentine wears away faster than the enamel, so the tooth is always chisel-shaped and sharp.
Rabbits, hares and pikas belong to the Order Lagomorpha, comprising 63 species world-wide. Only four species occur in Alberta, and are presented here. Like rodents, lagomorphs have a large space between the incisors and cheek teeth, lack canine teeth, and have continuously growing incisors. Unlike rodents, lagomorphs have two pairs of incisors on the upper jaw — a smaller, peglike pair directly behind the larger front pair.
Rabbits and hares are highly specialized for running by leaping and bounding. They have large hind feet and legs, and can move quickly to escape predators. Large, elongated ears enable rabbits and hares to detect noises at great distances.
