Rodents

There are many species of rodents. This large group includes such animals as squirrels, chipmunks, gophers, and rabbits. But the rodents that concern us most as household pests are known as commensal rodents. Commensal means "eating at the same table with," and commensal rodents are called such because of their close association with humans.

In the Greater Boston area, there are two commensal rodents of public health significance: the Norway Rat and the House Mouse.

 

Health Significance of Rodents

Rats and mice have vexed humankind since earliest recorded history. They are among the most significant of disease vectors. Consider the following:

• Fleas carried by rodents and infected with Yersinia pestis, the bacterium that causes plague, killed about one-third of Europe's population during the Great Plague of the 14th Century. Far from being extinct, plague outbreaks still occur and affect more than 3,000 people each year. In the last decade, Yersinia pestis has been detected in wild animals in the United States.

• Rodents also are implicated in the transmission of food poisoning, hantavirus pulmonary syndrome, leptospirosis, rickettsial pox, murine typhus, rat-bite fever, and other serious diseases.

• Rats and mice contaminate millions of pounds of stored food every year with their shed hair, droppings, and urine.

• Electrical fires caused by wiring that has been gnawed on by rodents causes untold millions in property damage, and many lost lives, every year.

• Rodents are also capable of causing serious injuries, especially to young children, who often see them as cute and attempt to play with them. Rodents have razor-sharp teeth and jaws that are adapted to gnawing, and their bites can cause serious injuries and infections.

 

Rodent Biology

By definition, the three commensal rodents are the Norway rat, the Roof rat, and the House mouse. All three of these animals share a few common characteristics, the most impressive of which is their reproductive capabilities. Look at the data in the following table:

	Norway Rat (Rattus norvegicus)	Roof Rat (Rattus rattus)	House Mouse (Mus musculus )
Sexual maturity:	2-3 months	2-3 months	About 6 weeks
Gestation period:	Averages 23 days	Averages 22 days	Averages 19 days
No. of young:	6-12 per litter	6-8 per litter	5-6 per litter
No. of litters:	4-7 litters per year	4-6 litters per year	6- 8 litters per year
No. weaned:	Averages 20 females	Averages 20 females	Averages 30-35 females

It's easy to see how even a few mice or rats in a building can rapidly grow into a major infestation. It's also easy to see why rodent control is a job for the professionals. For help in solving your rodent problem, contact the professional exterminators at Economy Pest Control.