The muskrat (Ondatra zibethicus), the only species in genus Ondatra, is a medium-sized semi-aquatic rodent native to North
America, and introduced in parts of Europe, Asia, and South America. The muskrat is found in wetlands and is a very successful
animal over a wide range of climates and habitats. It plays an important role in nature and is a resource of food and fur
for humans, as well as being an introduced species in much of its present range.
A vole is a small rodent resembling a mouse but with a stouter body, a shorter hairy tail, a slightly rounder head, and smaller
ears and eyes. There are approximately 70 species of voles; they are sometimes known as meadow mice or field mice in North
America. The voles, together with the lemmings and the muskrats, form the subfamily Arvicolinae.
The genus Microtus is a group of voles found in North America and northern Europe and Asia. The genus name refers to the small
ears of these animals. There are 62 species in the genus. These animals live in grassy areas. They are stout rodents with
short ears, legs and tails. They eat green vegetation such as grasses and sedges in summer and grains, seeds, roots and bark
at other times.
Lemmings are small rodents, usually found in or near the Arctic, in tundra biomes. They are subniveal animals and together
with the voles and muskrats, they make up the subfamily Arvicolinae (also known as Microtinae), which forms part of the largest
mammal radiation by far, the superfamily Muroidea, which also includes the rats, mice, hamsters, and gerbils.
The water voles are large voles in the genus Arvicola. They are found in both aquatic and dry habitat through Europe and much
of northern Asia. A water vole found in Western North America was historically considered a member of this genus, but has
been shown to be more closely related to members of the genus Microtus (Conroy and Cook, 2000; Musser and Carleton, 2005).
Head and body length are 12–22 cm, tail length is 6.5–12.5 cm, and the weight is 70–250 g.
The European Water Vole (Arvicola amphibius formerly called A. terrestris) is a semi-aquatic mammal that resembles a rat.
In fact, the water vole is often informally called the water rat. Some authorities consider the Southwestern Water Vole in
the same species, but it is now generally considered a distinct species. Water voles have rounder noses than rats, deep brown
fur, chubby faces and short fuzzy ears; unlike the rat their tails, paws and ears are covered with hair.
