When can rats give birth? - briefly
Female rats attain sexual maturity at approximately «five to six weeks» of age and can become pregnant soon after. Gestation lasts about «twenty‑one days», so litters are typically born roughly three weeks after conception.
When can rats give birth? - in detail
Rats reach sexual maturity between five and eight weeks of age, depending on strain, nutrition and ambient temperature. The estrous cycle lasts four to five days; ovulation occurs during the proestrus phase, allowing conception shortly after sexual maturity. Gestation endures twenty‑one to twenty‑three days, with minimal variation among laboratory and wild populations.
Key timing factors:
- Puberty onset: 5–8 weeks.
- Estrous cycle length: 4–5 days.
- Fertilization window: proestrus, typically 12–24 hours after cycle onset.
- Gestation period: 21–23 days.
- Post‑parturition estrus: occurs within 24 hours, enabling rapid successive litters if conditions permit.
Environmental influences such as photoperiod, cage density and food availability can accelerate or delay puberty and affect litter size. Lactating females may experience a brief anestrus, but the immediate post‑partum estrus often overrides this, supporting bi‑monthly breeding cycles under optimal conditions.