There’s an estimated population of over 7 billion rats currently living in the world. Rats can be traced back to over 160 million years of existence. Homeowners dealing with rats in their attics and walls may wonder how many rats are in my home and how fast can they reproduce?
A brief overview of rat biology will help answer these questions. Female rats are sexually mature between 4-6 weeks of age. Females will gestate for approximately 3 weeks and produce 4-12 pups/litter. Over their lifetime females will average 2-8 litters.
Because of their relatively short gestation periods and speediness to sexual maturity rat populations can boom over a year.
To make math easy let’s use an average of 8 rats per litter multiplied by 5 litters in a lifetime yielding 40 rats per female. If we assume half of the 40 pups to be female capable of producing 40 descendants each we would have 20 females times 40 offspring yielding 800 rats. The good news is rats have a high mortality rate and short average lifespan.
Rats are subjected to factors that naturally limit their populations. Rats are prey to many critters and subjected to natural predation. Rats are pathogen vectors, meaning they carry diseases that increase their mortality. These factors are accompanied by food and shelter limitations which help curtail rat populations. On average rats will only live to 1 year in the wild. We have found that most homes can support between 5-10 rats/ attic.
Rat removal efforts from houses should focus on trapping and exclusions. Traps are effective and make removal of carcasses easier than alternative methods like poisons. Thorough inspections of a homes exterior will highlight rat entrances that can be sealed to prevent re-infestations. “If they can’t get in they’ll stay out.”
For more information on rat removal and exclusions contact the wildlife professionals at Critter Evictors for your complimentary consultation.