Black Rat (Epimys rattus, Linn.).
Not many years ago a good deal of modified regret was expressed because it was thought that the Black Rat—the real old British Rat as it was called—was being exterminated by that vulgar upstart the Brown Rat—the Hanoverian or Norway Rat. These laments were mainly called forth by its comparative scarcity in old London warehouses where it had formerly been very numerous. One would have thought it a matter for rejoicing that there was a possibility of our having only one species of the rat pest to contend with instead of two. The disappearance of the Black Rat was remarked by Pennant as far back as 1778. However, later observations tend to show that the Black Rat is far from being extinguished even in the City of London, where the old type of warehouse is being rapidly replaced by ferro-concrete erections with carefully trapped drains. The intelligence of the Rat is equal to little impediments of that sort, and if it cannot get in by way of the basement it can climb walls and enter by the attic windows.
On the score of sentiment we need not distinguish between the Black Rat and the Brown. They are both Asiatic aliens, though the Black Rat had been settled here for several centuries before the Brown Rat followed in his tracks. Nothing definite is known as to the date of his arrival. Geologists assure us that he was not among the indigenes, for even the most recent strata yield no remains of his bones or teeth. He is known to have been on the other side of the dividing Channel in the thirteenth century, and to have reached England soon after, and quickly to have become a nuisance. He had a clear run of over four hundred years in which to occupy the most remote portions of the island, before he had to meet with keen competition in the form of the Brown Rat. He reached Ireland in the twelfth century, if not earlier.
The Black Rat is of more slender proportions than the better known Brown Rat, and much smaller, the dimensions of the head and body being about seven inches, whilst the scaly-ringed and almost hairless tail is more than eight inches. The long, pointed snout projects far beyond the short lower jaw; the whiskers are long and black. Though presenting the appearance denoted by its popular name, the glossy blue-black fur has a good sprinkling of grey on the upper surface, whilst below it is dark grey. The large, thin ears are naked, and about half the length of the head. The feet are pink, with scale-like rings on the underside of the digits and five pads on the sole. The thumb of the forefeet is reduced to a mere tubercle.
Although the Rats have much to do with garbage and offensive matters, they take the greatest of care to maintain their own cleanliness and a spruce appearance, spending much of their time in cleaning their fur and paws. One of the reasons for regretting the possible extirpation of the Black Rat by his more pushful relative, was, no doubt, his less ferocious ways and well-known milder disposition—a trait which is obvious to any one who has handled the domesticated albino, or White Rat, which is generally considered to be of this species.
Where—as in India—the Black Rat lives a more out-of-door life, it climbs trees and mostly makes its nest in them. With us the doe collects a good quantity of suitable materials—rags, paper, straw, etc.—and constructs a roomy nest which she uses for successive broods, which come at short intervals. Seven or eight is the usual number for a litter, and there are five or six broods in a year.
In the matter of food, both the Rats are omnivorous, and it is, therefore, useless to attempt to give a list of substances acceptable to them. Fish, flesh, fowl, or vegetable, crustacean or mollusc—anything that can be digested—is eaten by them; and if all else fails they will eat their own kin. In this matter the Brown Rat, from his superior size and ferocity, has the advantage, as is emphasised by an incident told by a professional rat-catcher to Frank Buckland. He said that having had a successful haul in infested premises he had turned all his captures both Black and Brown into a large wire cage, intending to have a little sport next day with a few cronies and a terrier or two. To his astonishment next morning all the Black Rats had disappeared and only the Brown—or some of them—remained.