The black rat, also called the roof rat, is much less common in our area than the larger brown rat. It’s usually found in more tropical, coastal areas. It’s the black rat and its fleas that were historically responsible for transmission of bubonic plague. Fortunately, plague has not been found in rats in the U.S. for many years.
Compared to the brown rat, the black rat is slightly smaller and more slender, and ranges in color from black to brown streaked with gray. You can also tell it from the brown rat by its larger ears, larger eyes, more pointed nose, and longer tail. It averages about 14 inches from the tip of its nose to the tip of its tail.
The black rat has a somewhat different diet and different habits than the brown rat. The black rat is more of a vegetarian, preferring to feed on plant materials like fruits, nuts, seeds, berries, and vegetables. But, like any rat, it will also feed on garbage and meats.
While the brown rat prefers to burrow, the black rat prefers to climb and travel above ground. It is very agile and easily travels along utility lines, fence tops, gutters, and tree branches. It gets its secondary name of roof rat because its climbing tendencies allow it to enter buildings through openings around the roof line. Unlike the brown rat’s burrow nests, the black rat usually nests above ground in trees, woodpiles, or wall ivy. Indoors, it nests in attics, roof insulation, false ceilings, and in rooftop cooling and A/C units. The nest can be constructed of leaves, grass, paper, or fabric.
It takes an expert to tell the difference between black rats and brown rats. Because of their different habits, they require different control methods.