Rabbits & Rodents

Rabbits and 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

Classification

Rodents form the largest group of mammals, classified under the Order Rodentia, comprising over 1600 species world-wide.

Characteristics

  • 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.
  • Of the 37 species of rodents in Alberta, only a few are regularly seen by people. Most are active at night (nocturnal) and secretive in behaviour.
  • Of the rodents featured here, marmots, red-tailed chipmunks and red squirrels are active during the day (diurnal); and the beaver, muskrat and porcupine are generally nocturnal.

Hibernating and non-hibernating rodents

The marmots (Genus Marmota) are large members of the squirrel family (Sciuridae). Marmots hibernate during the winter. Hibernation is an adaptation to the cold of winter, when an animal enters a dormant state.

In this sleep-like condition, the animal's body temperature, heart beat rate and energy requirements are reduced. Before entering hibernation in the fall, marmots store food energy in the form of body fat. This fat supplies the animal with all the energy it needs to stay alive until spring.

Beaver, muskrat and porcupine do not hibernate. They remain active throughout the winter and must continually find enough food to supply their high energy requirements during the cold winter months.

Species

In Alberta, there are 37 species of rodents. The eight rodents presented here include:

Rabbits, hares and pikas

Classification

Rabbits, hares and pikas belong to the Order Lagomorpha, comprising 63 species world-wide. Lagomorphs are divided into two families:

  • Leporidae (rabbits and hares)
  • Ochotonidae (pikas)

Rabbits and hares are the best known group, having the characteristic long ears and hind legs. They are mainly nocturnal in their habits.

Pikas look more like guinea pigs than rabbits or hares. Yet, they have the same tooth and skull structure as the latter, which places them firmly in the Order Lagomorpha. Pikas have short, rounded ears, and short legs. They are diurnal in activity and can often be seen in an alpine rock slide.

Characteristics

  • 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, peg-like 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.
  • Lagomorphs do not hibernate, and must spend the winter searching for food. The pika is the only lagomorph to store food in the summer for use in the winter.

Species

Only four species of lagomorphs occur in Alberta, and all are presented here.

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Updated: Jul 29, 2015