Pack rats, also known as woodrats, construct elaborate homes that offer shelter and protection in diverse environments. This article explores their varied geographical range and how they build their unique dwellings.
Geographical Range
Pack rats, belonging to the genus Neotoma, are widely distributed across North America, extending from Canada through the United States and into Mexico. Their range stretches from the Yukon and western Northwest Territories in Canada, covering most of the contiguous United States, and reaching as far south as western Honduras in Central America. Different species exhibit specific distributions within this continent.
For example, the eastern woodrat (Neotoma floridana) is found throughout the southeastern and midwestern United States, from central Florida north to southeastern New York and west to eastern Colorado. In contrast, the desert woodrat (Neotoma lepida) primarily inhabits arid regions of western North America, including southeastern Oregon, Nevada, Utah, California, Baja California, and northwestern Sonora. This extensive distribution highlights their adaptability to a wide array of climates and terrain.
Preferred Environments
Pack rats thrive in a variety of natural environments that provide both shelter and food sources. They can be found in arid deserts, rocky canyons, dense forests, scrublands, and mountainous regions, from low, hot deserts to cold, rocky slopes above timberline. Their presence is often linked to the availability of succulent plants, which serve as a primary water source, and adequate shelter from predators and extreme temperatures.
In desert ecosystems, species like the white-throated woodrat (Neotoma albigula) and desert woodrat utilize spiny cacti such as prickly pear or cholla for protection, incorporating these plants into their dens. Other species, such as the bushy-tailed woodrat (Neotoma cinerea), are found in rocky habitats and cliffs across boreal woodlands and deserts, relying on rock crevices for refuge. Forest-dwelling species, like the dusky-footed woodrat (Neotoma fuscipes), prefer dense chaparral, oak, and riparian woodlands with well-developed understories, or mixed coniferous forests. These varied environmental preferences demonstrate their ability to utilize diverse resources.
Constructing Their Homes
A hallmark of pack rats is their construction of elaborate structures known as middens or dens. These complex homes are built from various scavenged materials, including sticks, twigs, branches, rocks, cactus parts, bones, and human-made debris. The size of these middens can be substantial, sometimes reaching up to four feet high and eight feet wide, resembling a beaver dam.
These structures provide protection from predators, insulate against extreme temperatures, and serve as storage areas for food. Inside, a midden typically contains several nest chambers for resting, food caches, and specific areas for waste. Pack rats often urinate on these debris piles, and in dry climates, the urine crystallizes into “amberat,” a natural cement that binds materials together, creating a hard, resilient structure. This allows middens to preserve their contents for tens of thousands of years, offering valuable insights into past environments and climates.