by Angie Pollock

Created on: May 28, 2009

Once grouped together with the rodent family, lagomorphs are a part of two small orders of the Lagomorpha family. One group consists of rabbits and hares and the second includes pikas. Lagomorphs are believed to have evolved from the Asian grassland and meadow regions more than 50 million years ago. However, the largest emission of hares and rabbits has transpired in North America.

Lagomorphs are small herbivores with sharp incisors designed for chewing vegetation and shrubbery. While rodents also have these chisel-shaped incisors, there are differences in both the physical and behavioral characteristics of these two families. Lagomorphs have two sets of upper incisors with one rear pair that is sometimes referred to as "peg" teeth. Rodents do not have this extra set of teeth. Rodents are also not strictly herbivores and are known to forage on a variety of substances.

The digestive system of lagomorphs is similar to grazing ruminant animals. They both have a bag-like chamber within the digestive system where semi-digested food collects. This system in lagomorphs is not as vast as the larger ruminant mammals leading rabbits, hares, and pikas to consume their dung. Two types of pelleted dung are produced by lagomorphs. The harder pellets have been fully processed by the digestive system and are not eaten. Softer pellets sometimes called cecotropes are filled with protein, vitamins, and nutrients that is important to the animal's diet.

The pika resembles a small rodent with its small build and coat color ranging from buff to brown depending upon the species. This tailless mammal weighs from four to eight ounces and averages eight inches in length. Most species inhabit Asia with two species known to roam parts of North America. The average life span of the pika is only a few years but can survive up to seven years. Main predators of this small creature include birds of prey, wolverines, and ermines.

There are many species of rabbits and hares which can be found across the globe. While these two mammals do resemble each other there are differences. Both rabbits and hares are runners and use this ability along with leaping to escape danger. Both are primarily active during the evening and night hours. Both are used for human consumption in most parts of the world and domesticated rabbits are also known to be enjoyable pets.

Many still mistakenly refer to rabbits, hares, and pikas as rodents. These species of mammals are quite distinctive and have their own characteristics that have put them in an order all their own. The behavioral and physical differences set lagomorphs apart from all other species and even though these animals are considered as pests by some, this group of creatures is an important part of the environment.

References:

MAMMALS OF NORTH AMERICA, TEMPERATE AND ARCTIC REGIONS, by Adrian Forsyth, copyright 1999.

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