Pack rats
- By Susan Tweit
- Published 01/1/2003
- Outdoors
- Unrated
Susan Tweit
Susan J. Tweit is a scientist who evolved into an award-winning writer and radio commentator. She is the author of five books for adults, including Barren, Wild, & Worthless: Living in the Chihuahuan Desert, personal stories about the history and natural history of Southern New Mexico, The Great Southwest Nature Factbook, a browser's guide to nature in the Southwest, from A to Z, and Seasons in the Desert: A Naturalist's Notebook, from Chronicle books. She has also written two children's books, Meet the Wild Southwest: Land of Hoodoos & Gila Monsters (Alaska Northwest Books) and City Foxes, a picture book which was named one of the Outstanding Science Books for Children for 1998.
Her "Wild Lives" radio commentaries are heard three times weekly on KRWG-FM, Southern New Mexico public radio, and her columns run in the Las Cruces Sun News. Susan's essays and stories have appeared in Harrowsmith Country Life, New Mexico, Sierra, Cricket, Bloomsbury Review, and other magazines. She is the co-founder of Las Cruces' wildly popular - and fun - Border Book Festival. She is currently living in Colorado with her husband, Richard Cabe, and dog, Perdida Imelda.
Susan is a popular public speaker and leader of workshops. Her stories of our natural and human history have captivated a wide variety of audiences, including school classes, workshops, banquets, and professional meetings. As Bloomsbury Review put it, she brings the precision of a scientist and the passion of a poet, and is able to refocus readers' vision and ignite their imaginations.
Susan has a new web site! She invites you to come visit. Her books are available there, at local bookstores, or on-line through http://BarnesandNoble.com and http://Amazon.com (search by author for Susan Tweit).
I suspect from her description that the mystery burrow belongs to a pack rat, one of a kind of large rodents more closely related to mice than true rats. Named for their acquisitive nature, pack rats scavenge objects such as mesquite branches, spiny cactus pads, cowpies, newspaper, cloth, and aluminum cans and tote these treasures home to construct their nest, a conspicuous mound at the base of a tree or shrub, in a rock crevice, or in a building.
Pack rats are particularly attracted to shiny objects - watches, jewelry, coins, and, of course, aluminum cans. One nest even sported an upper denture plate! An average den of a desert-dwelling pack rat contains about 20 cubic feet of material - enough to fill a trash bag‹and may reach 4.5 feet high by 2 feet wide.
Building with trash is an elegant adaptation to the desert environment. Where construction materials are scarce, pack rats take advantage of what is easily available.
Further, the untidy-looking pile of debris provides excellent insulation, keeping the interior cool in summer and retaining the pack rat's body heat in winter. Inside one desert nest, the temperature never rose above 88 degrees F, despite searing ground-level
Choice pack rat nests may be occupied for hundreds or even thousands of years by successive generations of the nocturnal, plant-eating rodents. Even when abandoned, the nests and adjacent "trash middens" created when the occupants cleaned house persist in the arid environment, partly fossilized by varnish-like coats of pack rat urine. Such nests provide a window into the past: paleontologists and plant ecologists "read" the layers to learn about climates and plant communities dating back as far back as 25,000 years.
Molly's friends had never seen the occupant of the unusual burrow. Since pack rats are nocturnal, the best way to see one is to watch from a nearby vantage point at night with a flashlight. High-pitched, mouselike squeaks and a thumping gait give away the rodent's presence. (Pack rats are usually solitary except when raising young.)
Their large size (adults reach a foot to a foot-and-a-half long including their long, hairy tail) and their strikingly bicolored fur (dark above, light below) are unmistakable. Although pack rats' noisy, nocturnal habits and acquisitive nature make them nuisances when they take up residence inside houses and other buildings, these characteristic Southwest residents make fascinating outdoor neighbors.