Their dens are commonly located on the ground and measure 3 to 5 feet in height and diameter. One animal may inhabit several nests, and in good feeding areas a den may be occupied for several years or a lifetime. Pack rats live alone except when mating or rearing young. Circling of small trees and shrubs occurs but is not common. Rarely do they become numerous enough to cause more than very limited damage to flower or backyard vegetable gardens. Nationwide they are considered a pest of very minor occurrence; however, locally they may be relatively significant pests.
In houses, pack rats are active at night, searching for food and nest material. Pack rats are known for their characteristic searching of materials to bring back to their nests creating an ever-expanding collection. As the name "packrat" implies, they have a tendency to pack away small objects such as jewelry, utensils, can tabs, and other items. A peculiar characteristic is that if they find something they want, they will drop what they are currently carrying and "trade" it for the new item. They are particularly fond of shiny objects. They can also be quite vocal and boisterous.
Pack rats can cause extensive damage to your property. Not only do Pack Rats damage and destroy landscaping, they can also chew through wiring and spoil food. Woodrats may also shred upholstered furniture and mattresses for lining nests. Pack rats seek opportunities to nest in cars, A/C units and pool equipment and will chew through wiring creating thousands of dollars of damage. They may take up residence in parked vehicles, gnawing on wires and other mechanical components.
Wood rats climb readily and are chiefly nocturnal; occasionally they are observed during daylight. Their food is largely determined by varying local conditions and consists mainly of a variety of green vegetation including grass, leaves, fruit, nuts, small bulbs, bark, dry seeds and fungi. They also may be attracted to human food supplies in buildings.
Pack rat nests also harbor diseases other pests such as kissing bugs, brown spiders, mice and scorpions. Evidence that you have pack rats is gnawing and fecal pellets. When wood rats nest in buildings, they may utilize available foods within the building, but most often they continue to feed outside.