Ten Quick Bits on Rats

1. Size: Adult Brown Rats (aka the Norwegian Rat) generally weigh between 10 and 18 ounces and can reach lengths up to 18 inches, from nose to tail. The average weight of an urban rat is about 12 ounces.
   
   
2. Food and Water: : Rats can eat a third of their weight in food a day, but unlike other rodents, rats have a strong need for waterand will drink 1/2 to 1 ounce a day. Rats eat 50 pounds of food a year and can eat 1/3 of their weight a day. Favorite foods include oatmeal, potatoes, meat and cooked eggs. The U.S. Government reports that the average rat damages $1 to $10 worth of food and other material per year, and contaminates 5 to 10 times this amount in its travels. U.S. Food and Drug Administration (FDA) guidelines allow "an average of two rodent hairs per one hundred grams of peanut butter."
   
   
3. Senses: Rats follow the edges of walls or old grease trails left by their own bodies because they can see only three or four feet with any real accuracy. Rats have such an acute sense of taste, however, that they are able to detect some poisons at levels as low as 0.5 parts per million.
   
   
4. Reproduction: Litters of six to 12 young are born 21 to 23 days after conception. Young rats are completely independent at about four weeks, and reach reproductive maturity at three months of age. A female rat may have sex as often as 20 times a day and can produce a litter about six times a year. Most female rats are pregnant 100 percent of their adult life. A single pair of rats can theoretically multiply more than 15,000 descendants in 1 year; 359 million in 3 years. Like people, and unlike most other animals, rats display homosexuality, even when members of the opposite sex are readily available.
   
   
5. Locomotion: Rats can run at 24 miles per hour for short bursts -- about as fast as an Olympic runner, even though they weigh less than 1/100 the weight. Rats can swim 1/2 mile in open sea and tread water for 3 days. They can dive 100 feet underwater and hold their breath for as long as 15 minutes.
   
   
6. Not a Native Animal: Although the Black Rat has been in England since the Third Century AD, the first recorded Brown Rat arrived in 1714, along with King George I, and they may have come over on the same ship from Germany. The first Brown Rats arrive in the U.S. in 1760.
   
   
7. Rats Can Survive Anything: Warfarin was developed as a rat poison a couple of decades ago, but within a year of its introduction, some rats had grown so resistant to this powerful anti-coagulant that they were seen eating it for food. After several atomic bomb tests on Engebi, in the Eniwetok Atoll in the 1950s, scientists returned to the island to find highly radioactive soil, devastated plant-life, and a huge colony of perfectly healthy rats living off of dead fish washed up on the beach.
   
   
8. The Power of Rat Teeth: The jaws of a rat can exert pressures of 24,000 lbs per square inch, and rats can readily chew through plastic water pipes, bone, irrigation systems and garbage cans, wood boxes, dry wall, and even cinder block. On the international "hardness index" rat teeth = 5.5, while iron = 4.0, copper = 2.5-3.0, aluminum = 2.0 , and lead = 1.5. Rat teeth grow about 5 inches a year, and rats with mis-aligned jaws have been know to pierce their own brain cases with their incisors.
   
   
9. Getting Rid of Rats: It is is almost impossible to rid an area of rats by poison and traps alone. Some rats are simply too smart to be caught by traps, and rats grow resistant to any one poison pretty quickly. Poison and traps can work, but ONLY if they are combined with a clean up of garbage-ridden areas. Start by putting all trash into cans with tight-fitting lids, removing large overflowing dumpsters, trimming grass and weeds in the area, plowing up burrows, and removing all possible hiding places. Bird feeders should be removed, dogs cleaned up after, sources of water drained, and wood piles raised off the ground.
   
   
10. Life and Death: Rats have pushed more animals into extinction in the last 500 years than than any other cause. Most of these extinctions were caused by rats eating the eggs and fledglings of birds endemic to Pacific islands. Rats can transmit at least 35 diseases to humans, including leptospirosis (very common) and the Plague (very rare).While the Bubonic Plague (carried by the Black Rat flea) wiped out scores of millions of people in Europe between 1300 and 1700, the arrival of the Brown Rat in the early 1700s pushed out the Black Rats and Bubonic Plague pandemics in Europe and most of the rest of the world quickly abated. The relatively high quality of life enjoyed by most people in the world today is directly attributable to medical research made possible by generations of laboratory rats bred for more than 150 years from the "fancy" rats first collected by Jack Black, the rat catcher (and terrierman) employed by Queen Victoria.