When does a rat fully mature? - briefly
Rats become sexually mature at about 5–6 weeks of age, while complete physical development is typically reached by 3–4 months.
When does a rat fully mature? - in detail
Rats achieve reproductive capability early, typically between five and six weeks of age. Testicular enlargement in males and first estrus in females mark this stage. Physical growth continues beyond this point; skeletal length and body mass approach adult dimensions by eight to twelve weeks. Full somatic maturity, characterized by stable weight, complete ossification of long bones, and consistent estrous cycles, is generally observed around three to four months of age.
Key developmental milestones:
- Neonatal phase: birth to three weeks; dependence on maternal care, rapid organ development.
- Weaning period: approximately three weeks; transition to solid food, emergence of independent locomotion.
- Puberty onset: five‑six weeks; onset of gonadal activity, appearance of secondary sexual characteristics.
- Rapid growth phase: six to twelve weeks; increase in body length and muscle mass, maturation of the immune system.
- Adult stabilization: twelve to sixteen weeks; plateau in growth curves, establishment of adult behavior patterns.
Physiological indicators of complete maturity include:
- Consistent estrous cycles in females, lasting four to five days.
- Stable testosterone levels and fully descended testes in males.
- Full development of the cerebral cortex, supporting adult cognitive functions such as complex maze navigation and social hierarchy formation.
Relative to lifespan, which averages 2–3 years for laboratory strains, the period of full maturity represents roughly 10‑15 % of total life expectancy, allowing several breeding seasons before senescence.