The common brown Rat also know as the Norway Rat (Rattus norvegicus) Breeding Behaviour. This Rat is not technically a seasonal breeder, a mating increase occurs in the warmer months of the year. An average female is capable of giving birth approximately seven times per year. Around 18 hours after giving birth, females experience postpartum estrus, and mate again. This reproductive function is responsible for the huge birthrates of Norway rats, which can reach 60 young each year per female. After a short gestation period of 22 to 24 days, the litter of approximately 8 pups is born. The young are very small and underdeveloped. It takes 14 to 17 days for the young’s eyes to open. Newborns weigh an average of 5 grams and are milk-fed until weaning occurs at 3 to 4 weeks, and the young then leave the nest. Because of there rapid breeding rate its important to start the eradication process as soon as a Rat infestation has been found. Do you have a Rat problem ?? if so call Able2 Pest Control for a fast efficient service.