Critters of North Idaho: Bushy-Tailed Woodrat

Let’s face it: people really don’t like rats. On one hand, this is understandable. They steal our food (pooping and peeing on what they don’t take), the diseases they carry have killed more people in the last millennia than all wars and revolutions combined, and they cause around 1 billion dollars in damage in the United States every year.

On the other hand, these travesties are largely carried out by only two of dozens and dozens of species of rats: the brown rat and the roof rat. As a whole, rats really have an undeserved bad rap! Who knows? By the time you finish reading this article, you might even like rats and learn to see them as cool critters that we’re blessed to share this earth with.

The rat we’re focusing on today is the bushy-tailed woodrat (Neotoma cinerea). The first thing that separates this little guy from its pesty cousins is that it belongs to a completely different family. They belong to the family cricetidae, which means they are more closely related to lemmings, voles and hamsters than they are brown rats and roof rats, which belong to the family muridae. Bushy-tailed woodrats are 12 to 18 inches long and weigh between seven and 21 ounces. Their tails are much furrier than those of the “pesty rats,” resembling that of a small squirrel. They have large eyes and ears to help them navigate their environment in low-light conditions. One thing you may particularly like about these rats is that they only rarely reside in human structures. They prefer to build their nests in craggy cliffs, canyons, outcrops, and caves of high elevation in the western United States and Canada.

If you have a habit of hoarding things, you may share this rodent’s more well-known name: the packrat. Like us, bushy-tailed woodrats have an obsession with collecting things from their surroundings. Woodrat favorites include sticks, bones, vegetation, and manmade objects, especially if they’re shiny! In fact, they’re so infatuated with shiny objects that they will drop whatever they’re carrying in their mouth if the shimmer of a metal utensil or coin catches their eyes. They take these objects to their nests, which are called middens.

The oldest woodrat middens are thousands of years old and date back to the Ice Age. The reason they last so long is because their urine, with which they frequently douse their midden, is highly concentrated. As it dries, it hardens into a rock-like outer coating. Bushy-tailed woodrats are often thought of as “nature’s historians” because they allow paleontologists and paleoclimatologists to learn what the environment was like when the midden was made. All they have to do is study the tiny bones and plant matter the rats used in the midden’s construction.

One of the amazing things they have discovered is that the climate of the western United States during much of the Ice Age was cooler and wetter than today. The area could support a much wider variety of lush plants and animals than it does today.

When not preserving artifacts in their natural “time capsules,” woodrats are hoarding food for the winter. They don’t hibernate like other rodents, so they need to cache large quantities of plant shoots, seeds, twigs, fruit, and a few insects in order to survive.

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