How long does it take for domestic rats to reach maturity? - briefly
Domestic rats usually become sexually mature between five and seven weeks old, while they achieve full physical maturity around three to four months of age.
How long does it take for domestic rats to reach maturity? - in detail
Domestic rats (Rattus norvegicus) reach the weaning stage at three to four weeks of age. After this point, rapid growth continues, and the onset of puberty typically occurs between five and six weeks. Full reproductive capability is usually attained by eight to twelve weeks, with females often maturing slightly earlier than males.
Key factors that can accelerate or delay this schedule include:
- Genetic line (laboratory strains mature faster than wild‑type stock)
- Nutritional quality (high‑protein diets promote earlier development)
- Environmental conditions (stable temperature, low stress)
- Health status (absence of disease or parasites)
Observable indicators of sexual maturity are:
- Descent of testes in males, accompanied by increased size and a change in scent
- Onset of estrous cycles in females, manifested by vaginal swelling and behavioral receptivity
- Body weight reaching 150–250 g for females and 200–300 g for males
- Increased territorial and mating behaviors, such as mounting and frequent vocalizations
For breeding programs, separating individuals before the eight‑week mark prevents unintended litters, while monitoring the listed signs confirms that rats have reached reproductive age. Regular health checks and a balanced diet support optimal maturation timing.