How many months do rats grow? - briefly
Rats become sexually mature at about 5–6 weeks and achieve full adult size by 3–4 months of age. Growth then plateaus and body weight remains stable.
How many months do rats grow? - in detail
Rats reach full physical development within a relatively short span. After a gestation of 21‑23 days, newborns are weaned at about three weeks. By five to six weeks, males can reproduce, while females become fertile around six to eight weeks. Body weight and length continue to increase for another four to six weeks, after which growth plateaus. Most laboratory strains attain adult size by three months of age. Beyond this point, weight stabilizes, and physiological changes shift toward maintenance rather than growth.
Key milestones:
- Birth to weaning: 0–3 weeks – rapid organ maturation, reliance on maternal milk.
- Juvenile phase: 3–6 weeks – introduction of solid food, skeletal growth accelerates.
- Sexual maturity: 5–8 weeks – testes descend in males, estrous cycles begin in females.
- Adult size: 10–12 weeks – body mass reaches 250‑300 g for common strains; length approximates 20 cm.
Environmental factors such as temperature, diet, and strain genetics can modify the timeline by a few days, but the overall pattern remains consistent across most domesticated rats.