[1] Neotoma includes three subgenera, Daggers (†) mark extinct species:[2] Packrats typically have wide eyes accompanied with long whiskers.

[6] In general, packrats' backs are notably a hybrid hue of brown and grey, but their underbelly tends to be a lighter shade.

Pack rats live anywhere from low, hot, dry deserts to cold, rocky slopes above timberline.

Pack rats build complex houses or dens made of twigs, cactus joints, and other materials.

Dens are often built in small caves or rocky crevices, but when close by human habitations, woodrats will opportunistically move into the attics and walls of houses.

Others, like the desert woodrat (N. lepida), will build dens around the base of a yucca or cactus, such as jumping and teddy-bear chollas.

They are cliff-dwellers and are often found on isolated, high-elevation exposed boulder areas under a variety of temperature and moisture conditions.

[10] The pack rat microbiome has symbiotic roles in digestion, recycling endogenous nitrogen, and the detoxification of dietary toxins.

[11] The bacterial composition of the pack rat’s gut microbiome is affected by what it eats, and by association, the geography of where the animal is from.

Examinations and comparisons of pack rat middens have largely supplanted pollen records as a method of study in the regions where they are available.

Paleo-ecologists have used a variety of techniques to analyze the plant and animal material in pack rat middens describe paleo-communities and infer paleo-climate.

[15] The analysis of middens was key in understanding the biota around Pueblo Bonito, thus helping to explain its history.