The shrew and the vole are 2 more tiny mammals that inhabit the Denali National Park area. The ermine, ground squirrel, pika and lemming were all described in earlier articles, but these 2 species are even smaller. Read the following descriptions and then try to guess which picture belongs to which animal.
The shrew is a solitary animal that is not a rodent although it resembles one. It has tiny eyes resulting in poor vision and sharp, spike-like teeth. Its teeth do not continuously grow as in the rodent and they have only one set in their lifetime. The adult shrew is about 3.5 inches in length, which includes a long tail, and weighs about 3 ounces. The shrew is an opportunistic omnivorous feeder and will eat the remains of animals left by other predators. This results in a high death rate from parasitic infections and may account for the multiple litters that a female will have, up to 10 litters a year, with 6-7 babies in each litter. Females are very territorial and some species of shrew can poison an opponent. They live in shallow burrows and tunnel their way through leaf litter.
The vole is in the rodent family. It is about 3 inches in length, and weighs about 2 ounces. It is also an opportunistic feeder but prefers plants. It can be quite destructive to vegetation, eating around the base of small trees and eating the root systems. Both the vole and the shrew are voracious eaters, and can consume the equivalent of their body weight in one day. Though their eating habits can be destructive, both species are a valuable part of the ecosystem because of soil aeration and because of their place in the food chain. Voles nest under grass and will also build burrows. Like the shrew, their reproduction rate is high, having 5-10 litters a year. And, also like the shrew, the female vole is very territorial.
Neither animal hibernates and both species have common predators, including martens, owls, coyotes and foxes. My dog would like to be included in the list of predators but she has never actually caught a vole or a shrew. But she tries real hard.
Are you able to guess which picture is which animal? The picture on the left hand side is the vole. The shrew on the right has the tiny eyes and long tail.