Adaptations for the Northern Red-Backed Vole

Coat Color

• Different populations of northern red-backed voles have different coat colors depending on their environment. In the coldest regions of the tundra, the voles often have pale coats. This coloring makes them less conspicuous to their many predators, including birds of prey and small mammalian carnivores. In slightly warmer regions, the voles usually have russet-brown coats, which blend in effectively with the leaf litter covering their forest habitat.

Size

• A similar adaptation can be seen in the size of the voles. Those of tundra regions tend to be larger than those of warmer areas. According to the Smithsonian Museum of Natural History, this is probably an adaptation to colder winters. Larger voles have greater fat reserves to sustain them during food shortages.

Hoarding

• The northern red-backed vole is primarily an herbivore, although it is not averse to eating small prey, such as insects, when available. During the spring and summer, the supply of seeds, nuts, berries, lichen and other plants is abundant. During the winter, the supply dwindles to nearly nothing. For this reason, the voles stash as much food as they can during the fall, to sustain them over the winter months. This is a common adaptation in the small animals of cold regions that do not hibernate. They have a high metabolism and cannot go for long without food, so well-stocked larders are essential.

Tunnels

• To stay out of sight of predators and away from the elements, red-backed voles create extensive tunnel systems under the snow. Interestingly, they have adapted to the presence of human habitations by sometimes coming inside homes during the winter. They tend to stay away from houses during the spring and summer. Presumably, the threat posed by large mammals such as humans and their pets is not worth the risk for the ready-made, warm shelter of human homes when weather conditions are not so extreme.

Territories

• Among the behavioral adaptations of red-backed voles is a tendency to be territorial. Territories are important when one of the primary factors affecting the survival of an individual is the food supply. How territorial an individual vole is depends upon its gender and social role. Breeding females, whose need for a large area is greatest, have clearly defined territories that do not overlap the territories of other females. Breeding males have territories that overlap both the territories of the females and the loosely defined territories of non-breeding males.