Check insulation for nesting sites, inspect exposed wiring for gnaw marks, and listen for the sounds of rats running or digging inside walls, attics, garages, or chimneys. Look for signs of hollowed-out fruits, capsule-shaped droppings about ¼ to ½ an inch in length, gnaw marks on your home or trees, grease and urine stains, live or dead rats, or rodent odors.
Since roof rats may enter your home through ill-fitting doors, windows, screens and air vents, seal any openings with caulk, wood, and mesh, and secure floor drains and sewer pipes with tight-fitting grates. Keep garbage cans tightly secured, store bulk food in sealed plastic containers, and check for sources of standing water, since roof rats need an ounce of water a day. To make an ideal home, roof rats need food, water, and a cozy nesting site, so clean out wood piles, rake up fallen vegetation and fruit, and do not leave pet food or water outside, especially overnight. To prevent rats from entering your home, seal up any holes or cracks larger than a quarter. Though they will eat meat and grain, roof rats love to feed on fresh fruit, plant materials, nuts, seeds, vegetables, tree bark, and bird feed. Becoming sexually mature in a matter of months, roof rats typically have 5-8 babies per litter and 4-6 litters per year.
In late fall, roof rats seek out warm nesting sites like the upper levels of your home or garage. Though they may be cute, these critters can cause major damage by chewing on housing materials and eating stored foods. Skittish, smooth-furred, and not well adapted to cooler temperatures, roof rats are often mistaken for house mice. Smaller and with longer tails than Norway rats, roof rats are well adapted for climbing vines, wires, ropes, and narrow ledges.