The New International Encyclopædia/Rat

RAT (AS. raett, OHG. ratto, Ger. Ratte, Fr., Prov. rat, It. ratto, rat; of uncertain etymology). Any of the larger rodents of the genus Mus. (See Mouse.) Two species are very widely distributed over the world — the black rat (Mus rattus) and the brown rat (Mus decumanus) . Both appear to be natives of Central Asia. The black rat found its way to Europe about the beginning of the 16th century, but the brown rat did not reach England until about 1728. The British Jacobites were accustomed to delight themselves with the notion that it came with the House of Hanover, and chose to call it the ‘Hanoverian rat.’ It also received the name of ‘Norway rat,’ from a belief that it was introduced from Norway. The date of introduction into America is very doubtful, but the black or Alexandrine rat seems to have come first, and has been gradually driven westward by its large and more savage cousin. The brown rat is the larger and more powerful of the two, and has waged war against the other with such success as to cause its total, or almost total, disappearance from many districts where it was once abundant, yet in some places the black rat is still the more plentiful of the two. Both infest ships, and are thus conveyed to the most distant parts of the world, and both are ‘wharf rats.’

The black rat is nearly 7½ inches in length, exclusive of the long tail. The brown rat attains a length of more than 10½ inches. Besides its large size and comparative shortness of tail, it differs from the black rat in its smaller ears and less acute muzzle, as well as in its lighter color and shorter hair. Both species are extremely prolific, breeding at a very early age, several times in a year, and producing from 10 to 14 at a birth.

Rats feed indiscriminately on almost any kind of animal or vegetable food; they make depredations in fields of grain and pulse, from which they often carry off large quantities to be stored in their holes, and thus have become a serious pest in the West Indian sugar plantations. They devour eggs; they kill poultry, partridges, and the like, and become a pest of ill-kept dwellings and storehouses. Their strong rodent teeth enable them to gnaw very hard substances, such as wood and lead pipes, either for food or in order to make their way to food. They are creatures of no little intelligence, and many curious stories are told of the arts which they employ to attain desired objects, of the readiness with which they detect the approach of danger, and the skill with which they avoid it. Under certain circumstances they undertake migrations in large companies. Their sense of smell is very acute, and the professional rat-catcher is very careful that the smell of his hands shall not be perceived on the trap. They are capable of being tamed, and have in some instances proved interesting pets.

The flesh of rats is seldom eaten. The skin is used for making a fine kind of glove-leather. During the prevalence of the bubonic plague in India, Australia, and Cape Colony, in the latter part of the nineteenth century, it was ascertained that there was a direct connection between the prevalence of the disease and the abundance of rats, and it was shown that the rats were themselves liable to the plague, and myriads perished from it. Investigation showed that the fleas, with which rats are infested, are hosts for the plague germ, and that thus rats unwittingly served as an important means for spreading the disease. Measures were taken, in consequence, to kill them in the ports of India in large numbers.