Mice and rats reproduce rapidly because of short gestational periods and rapid sexual maturity. The reproductive cycle and number of rodent offspring increases where food and water are adequate, of course, harborage is another factor to their final number.
Mice become sexually mature and able to mate in as little as weeks. In general, sexual maturity is reached in 5 to 8 weeks.
Female mice reporduce up to 8 times in their lifespan, with litters averaging 4 to 7 pups. Therefore, a single female may produce up to 56 offspring a year.
Norway and roof rats become sexually mature and able to mate at 8 to 12 weeks.
Norway rats average 8 to 12 pups per litter, averaging 4 to 7 litters per year.
Roof rats average 4 to 8 pups per litter, averaging 4 to 6 litters per year.
Plague is a communicable disease of animals and humans caused by a bacterium called Yersinia pestis. This is primarily an infection of rodents.