How Many Rats in a Litter?
WouterTypically, rats breed in January, but a cold winter or exceptionally dark winter can delay breeding. Also, longer days and hotter summers can affect fertility. The does are not fully mature when they are born, and they will continue growing until they reach about a year old. During lactation, they produce growth hormone.
A rat litter typically consists of six to twelve babies. A rat’s gestation period varies from species to species, but the average is approximately 22 days. It is common for a female to give birth to as many as eight pups during the gestation period. It is also common for a rat to produce litters every three to four weeks, so it’s possible for her to have up to 17 litters a year. The babies in each litter will be between six and twelve days old, and will be deaf and blind.
Rats are prolific breeders, with an average of eight pups per female rat. Female rats typically produce five litters a year. A female Norway rat can produce 12 pups, while a female roof rat can give birth to up to five to eight babies. Each female can have up to eight litters during her lifetime, so there’s a high likelihood that you will be dealing with an infestation in a short time.
The number of adult rats that a rat mate with also affects the number of eggs produced. Some breeders choose to mount males and females together only while feeding the rats. This method can result in a large litter with as many as 14 rats.
