Rodents
www.wikipedia.org
What are Rodents?
The order Rodentia is the most numerous of all the branches on
the mammal family tree. Currently there are, depending on the
authority consulted, between 2000 and 3000 species of
rodent—roughly half of all mammal species.
Rodents are found in vast numbers on all continents except
Antarctica (they are the only placental order other than the
bats to reach Australia without human introduction), most islands,
and in all habitats bar the oceans.
Most rodents are small. The tiny African Pygmy Mouse is only 6 cm
in length and 7 grams in weight. On the other hand, the Capybara
can weigh up to 45 kg (100 pounds) and the extinct Phoberomys
pattersoni is believed to have weighed 700 kg.
Rodents have two incisors in the upper as well as in the lower
jaw which grow continuously and must be kept worn down by
gnawing; this is the origin of the name, from the Latin rodere,
to gnaw. These teeth are used for cutting wood, biting through
the skin of fruit, or for defense. These teeth have enamel on the
outside and exposed dentine on the inside, so they self-sharpen
during gnawing. Rodents lack canines, and have a space between
their incisors and premolars. Nearly all rodents feed on plants,
seeds in particular, but there are a few exceptions which eat
insects or even fish.
Why are rodents important?
Rodents are important in many ecosystems because they reproduce
rapidly, and can function as food sources for predators,
mechanisms for seed dispersal, and as disease vectors. Humans use
rodents as a source of fur, as a model organism in animal
testing, and even in detecting landmines.
At the top of this page you will see a link for Small Pets,
click on that to find out more about Rodents as Pets.
