Adult rats can weigh anywhere from 5-16 ounces and measure 6-10 inches long. They have large ears and a pointed nose. A rat’s fur can be either smooth or shaggy depending on the type of rat. Their droppings are 1/4 to 1/2 inch in length, capsule shaped, with blunt ends. Rats will leave a hind foot track of about 3/4-1 inch where a mouse's track measure's 3/8 of an inch or less. They will also drag their tails, leaving a mark between their feet tracks. Tracking powder can be dusted to help determine their runways as they cross suspected areas.
Young rats reach sexual maturity in two to three months. Females will average four to seven litters a year, with eight to twelve pups per litter. Adults live for about a year. They live in colonies. Rats will seek food outside, but many times will come inside at night to forage for food and return to their burrows. As the rat family grows, more burrows are built, resulting in a network of underground tunnels. Inside, rats commonly nest on the lower levels, but if the population is too large, they may be found in the attic and ceiling areas. Their nests are built from soft material like paper or grass chewed into small pieces. Rats will climb if necessary to enter a building. They can also be good swimmers. Rats are suspicious of changes in the environment or new foods, for this reason it may take a couple of days for traps or baits to take. Rats are nocturnal, with their peak activity at dusk or before dawn. They can be seen during the day when their population is large or they are disturbed or hungry.