The Black Rat has a black to brown upper body with a lighter-brown or slate-colored underbody. It has a scaly, almost hairless tail that is slightly longer (7 to 9 inches) than its head and body, for a total length of over 14 inches. It has 5 digits on each foot and 16 very sharp teeth. Black Rats are thought to live for up to 4 years. The Black Rat is omnivorous, eating seeds, nuts, vegetables, fruits, insects and invertebrates. It will also eat other materials such as soap and paper. It has been observed to carry food back to the nest for storage. Under normal conditions the female will have between 3 and 7 litters per year, producing between 6 and 22 young per litter.

Black rats adapt to a wide range of habitats. In urban areas, they are found around warehouses, residential buildings, and other human settlements. They are also found in agricultural areas, such as in barns and crop fields. In urban areas, they prefer to live in dry upper levels of buildings, so they are commonly found in wall cavities and false ceilings. In the wild, Black rats live in cliffs, rocks, the ground, and trees. They are great climbers and prefer to live in palms and trees, such as pine trees. Black rats are also found around fences, ponds, riverbanks, streams, and reservoirs.