Forest Preserve District of Cook County, Illinois
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Nature Bulletin No. 81   August 31, 1946
Forest Preserve District of Cook County
Clayton F. Smith, President
Roberts Mann, Superintendent of Conservation

Rats and men have been at war since the dawn of history. The "cradle of mankind" Central Asia, apparently was also the place of origin of the rat. From there, living and traveling with man, it has spread over the globe. In the United States today there are about as many rats as there are people.

Cur common rat is the Norway or brown rat which arrived here from Europe before the Revolutionary War. Fiercer and more cunning, it soon exterminated the black rat and the roof rat which had migrated here with the early colonists and thrived. The black rat -- which is glossy black above, smaller and more slender -- and the roof rat, a close relative, are found now only rarely in some of the southern states, although still common in tropical America.

These three rats and the common house mouse, another immigrant, are distinguished from our native rats and mice by having three rows of tubercles along the crowns of their molar teeth. Cur principal native rats are the rice rat, the cotton rat, and that friendly nuisance: the wood rat or pack rat.

The Norway rat is the most destructive animal in the world. In the United States, each year, they consume and damage foodstuffs and property valued at hundreds of millions of dollars. Infested with fleas, and commonly living in cellars, refuse dumps and filth, they transmit many serious human diseases, including typhus and bubonic plague. They are hated, loathed and feared. They possess acute senses, particularly the sense of smell, and a high degree of animal intelligence. They are extremely adaptable. They are omnivorous and will eat their own kind or even attack man if starved. They breed rapidly, having 6 to 20 blind naked young in a litter and 6 or more litters per year which mature and begin breeding before the age of six months.

About the only redeeming feature of the rat is the fact that, having lived with man and eaten the same foods for thousands of years, they react alike to the same diseases and the same treatments. Special strains are bred and experimented upon in laboratories to find the cause and cure of many human ills.

Red squill, the specific poison for rats, causes other animals to vomit. That is one thing a rat cannot do.

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