White-throated woodrat (Packrat) (Neotoma albigula)
Main source: Hoffmeister, Donald, 1986, Mammals of Arizona, Tucson: University of Arizona Press.
Woodrats -- members of the Genus Neotoma -- are large-bodied and long-tailed rats with (in our Arizona forms) relatively well-haired tails. The White-throated Woodrat is found throughout Arizona, while the Mexican Woodrat (N. mexicana) may occur in our general area but is more of a montane species. White-throated Woodrats have a definite association with stands of Cholla and Prickly Pear cacti, which they use to build their nests, cutting the cacti into 3-4"-long pieces and carrying them to the nest site in their mouths. The cacti parts serve both as nest-protectors and as food. The nest consists of two parts -- the house (the collected material, which is mostly above ground) and the nest (which is usually dug partway below ground). There may also be some underground tunnels leading to the nest, which is built of fine grasses or shredded fibers and about 6" in diameter, with an interior cavity about half that size. This serves as a daytime retreat (well shaded from the intense summertime heat) and as a nursery.
These woodrats feed mainly on Cholla cacti where these are available, or on Prickly Pear. They may therefore need to drink no free water. This one below has constructed its nest in a pile of fallen saguaro limbs, filling in the gaps with protective materials with a variety of cacti and other plant materials brought from locations nearby.
In the past, our efforts to photograph packrats were largely unsuccessful -- on one noteworthy occasion, the Infrared camera setup had its extension wire bitten through by one of these beasts the very day of its installation. Our first marginal success was the following video captures, stills of which give some idea of both nest and animal. On this occasion, in February 2001 we were moving some scrap lumber which had been lying in place for some years on a terrace in lower Hot Springs Canyon, and within which a packrat had built an extensive nest in the mess. Here, below left, David Omick (extended arms visible at upper left) lifted a piece of plywood to reveal the packrat hiding right in its nest, which is in a depression dug out of the soil beneath the plywood, directly in the center of the photo. You can make out the animal, slightly blurred as it begins to make its escape, at the lower edge of the nest, and also see something of the nest materials. Below right, the packrat scampers off towards the boards at the right, forming a distinct blur.(Click on the image to enlarge it.) Here the nest materials are more visible.
We then proceeded to remove the layer of piled boards, underneath the last of which we found the packrat hiding in one of its runways, below left; (Click on the image to enlarge it.) Here, the tail of the animal lies in the runway, while the packrat looks away from us toward a route of escape. But then it swung around, and lept over the nearby boards, below right, where we got our best still image. (Click on the image to enlarge it.) Hoffmeister (pp. 404-5), who has measured the White-throated Woodrat carefully by measuring specimens around the state, shows body length between about 6 & 7 inches, tail length somewhat shorter. This looks about right for this one. We may also be seeing a hint of the "white throat" in the image at right.
We have since had better luck, again while moving some lumber and junk which had been protected for several years under a canvas tarp. In January 2005, we encountered the unfortunate resident of a rather elaborate nest under this tarp:
Length of tail and of body look very similar in this image. Note the pieces of cholla cactus under the tail. The aluminum bars at lower left are the telescoping ribs of a defunct tent, while the plastic at the top of the photo is an empty gallon bottle. The exposed packrat took momentary shelter, below, under some old Agave stalks: (Click on each image to enlarge it.)
Hints of the "white throat" are evident in both of these images. We might note that this animal was afterward left to its own devices. It might return to the same location (where it had a rather elaborate nest, the fruits of much labor and no small creativity), but we found it necessary to remove this particular pile of junk so it will have to adapt in some other way. Unfortunately, this meant that such features as two distinct core nests, beautiful structures shown below, were exposed and largely ruined. We're not sure what the one on the left was made of; the one on the right was made largely of a flowering annual of some kind. (Click on these images to enlarge them.)
In the future we may consider trapping Packrats whenever we find it necessary to undo one of their nests, in order to remove them to some more suitable potential place of occupation, and even perhaps to move some of their hard-won structures to the new locations. However one deals with Packrats, however, we need to remember that their nests usually house considerable numbers of Cone-nosed Bugs, and be alert to the presence of these potentially dangerous insects See that link for further details.