Rats memorize specific pathways and use the same routes habitually.  Rats can get  into your home through a hole about the size of a quarter.Rats damage structures, chew wiring and cause electrical fires, eat and  urinate on human and animal food,  and carry many diseases. Thousands of  rat bites are reported each year in the  U.S. alone  and many go unreported. Accidental  poisonings occur among  humans and pets from poorly planned efforts to poison rats. Within urban  areas, rats  derive their life supports from waste- management systems and food processing and storage areas. Rats rely predominantly on smell,  taste, touch  and hearing  as opposed to  vision. They move around mainly in the dark, using their long,  sensitive whiskers and the guard hairs on their  body to guide them. Rats are cautious, and if their food is in an exposed  area where it cannot be consumed quickly, they usually carry or drag it to a  hiding place.

Rats have an excellent sense of taste, enabling them to detect certain compounds, including rat poisons, at extremely low contrations  very quickly. Rats are omnivorous, eating nearly any type of  food, including dead and dying members of  their own species. The Chichineca-  Jonaz, in the Mexican state of Guanajuanto, were eating  rats as part of their basic  diet as late as 1950. Rats continue  to be important food items in many countries, and the large  grass-cutter rat is caught and raised for market sale in  some African  countries  much as rabbits are in American and European markets The word "mouse" can be traced to the Sanskrit word "musha"  which is  derived from a  word "to  steal." 

Of all the mouse species that invade human structures,  only the house mouse usually becomes a  long-term  inhabitant if  not controlled.  Some scientists  speculate that  mice developed  from rats  under  conditions  where it was  less important  to be large and ferocious than to be able to get into a smaller  hole. Mice are more  acceptable to humans than rats, possibly because of what is known as the "Disney influence."

Mice are capable of being transported for long periods of time in closed containers,  such as  boxes, trunks or barrels. The house mouse is found throughout the world from the  tropics to the Arctic regions. There are believed to be  about 300  separate  varieties of  house mice in  the United States. The house  mouse has a  protective mechanism that responds to environmental  stress  excessive  heat for  example - by  inducing a  torpor or dormancy that conserves its physiological reserves.

Many fires of  "unknown  cause" may  have been  caused by  mice chewing  through electrical  wires. In six months, one pair of mice can eat  about four  pounds of food and  produce some 18,000 fecal droppings. Mice feeding  on colored  crayons will  produce  droppings based on the  color of the  crayon they were feeding on. Mice are not   blind but have  bad vision and  cannot see   clearly beyond about six  inches.