Adults with combined head & body length are 6-8", Tail length 7-10". Usual weight 150-250 gms but can grow to 340 gms. Fur is soft & smooth.
Color is usually brown with black intermixed to gray to black above with the underside white, gray or black. Muzzle is pointed, Ears are large. Tail is scaly and uniformly dark, longer than head and body combined. The droppings of the adult rat are upto 0.5" long spindle shaped with pointed end.
Roof rats reach sexual maturity in 2-5 months pregnancy lasts an average of 22 days. The young are blind & naked at birth, with hair appearing in 7 days and eyes opening in 12-14 days. They are weaned at about 3-4 weeks. The average number of litters is 4-6 per year, Each containing an average live 9-12 months. They have poor vision & are colour blind. The roof rat requires 14-28 gms of food & about 30 ml of water each day, with water often coming from their food. This intake of food & water results in 30-180 droppings & approx. 16ml of urine.
Roof rats are primarily nocturnal in habit and they are very cautious. They are constantly exploring their surroundings and shy away from new objects & change. As their name indicates, Roof rats prefer to nest in the upper part of structures, but may also be found under buildings occasionaly in basements and sewers. Roof rats eat anything, but never fruits, vegetable and cereals. If they find that a particular food material proves disagreeable, they are quick to develop food/bait shynes.
The key to any rat control program is Pest Identification, Sanitation, Harborage Elimination & Rat Proofing the Building. Some important things to remember are: (a) Rats defecate where they spend most of their time. Use the droppings as an indication to concentrate the control effort. (b) Rats travel 100-150 ft for food/water along established paths. Look for rub/swing mark.