The difficulties that have surrounded these animals in their free life have allowed them to achieve a refined reproductive system capable of perpetuating the species to unsuspected limits. That is why rats and mice are very jealous throughout the year, without any specific breeding season.
There are ways to avoid reproduction in rodents: avoiding contact between males and females or applying means of control of reproduction in the specimens that live at home. Check with your vet.
If we do not pay attention and we have a couple of rodents living in our home, in a short time, especially rats and mice, we will have a huge offspring that we will not know where to place or have enough time or money to maintain.
As we surely want not to reach that situation, it is best to inform ourselves and be responsible. If we decide to adopt a female and a male from any rodent, we must know from the beginning that there will be a danger that they will breed once they have reached sexual maturity. Today we give you some brushstrokes of when they reach that point and other information that will be of interest.
From the 15 days of gestation they will begin to build the nest for the birth
In rats and mice, pregnancy can be diagnosed with practice and by gentle palpation during the last third of pregnancy.
The mammary development of the females is very noticeable from the 15th or 16th day of gestation. A few days before calving is when they begin the construction of the nest: the animal prepares large quantities of material for the bed.
Remember not to disturb the female after giving birth, for three or four days. Excessive handling could cause the female to eat her young. This phenomenon is especially dangerous in rats.
The young are relatively immature at birth: they have neither vision nor hair, but they grow very quickly.
If it is raised, it is important to separate the male from the female before the young are born, otherwise the couple can mate again 12 hours after giving birth, causing an “overproduction” of animals .
These small rodents are sexually mature at six to seven weeks of age. After getting pregnant, the female mouse will last only 19 to 21 days of gestation, although it can last 28 days if the female is crossed in the first heat after giving birth. Each litter is usually 8 to 12 young, with an average of 7, but they can reach 20 specimens. A curious fact: the largest litter of a mammal in the wild was that of a female mouse in 1961: 32 young! Poor animal…
The number of litters per year ranges from four to eight. The young weigh one to three grams at birth.
In the case of rats, they become sexually mature 40 to 60 days after birth. Record time.
If a female becomes pregnant, her gestation period will last from 20 to 22 days and she will have between six and eight litters a year. In each litter there will be from six to 16 young, with an average of 11. These new rats will weigh five or six grams at birth.
