How often do mice give birth and how many pups are born? - briefly
Female mice can breed roughly every three weeks, with a gestation period of about 19‑21 days. A typical litter contains 5‑10 offspring, averaging six to eight pups.
How often do mice give birth and how many pups are born? - in detail
Mice reach sexual maturity at 5–6 weeks for females and 6–8 weeks for males. After a successful mating, the gestation period lasts 19–21 days. Consequently, a healthy adult female can produce a new litter roughly every three weeks, provided she has continuous access to mates and adequate nutrition.
Litter size varies with strain, age, and environmental conditions. Typical domestic laboratory strains (e.g., C57BL/6) average 6–8 pups per litter, while wild‑derived or larger breeds may yield 8–12. Very young or aged females often have smaller litters, sometimes as few as 2–3 pups.
Key reproductive parameters:
- Estrous cycle: 4–5 days, allowing multiple possible conceptions per month.
- Post‑partum ovulation: occurs within 24 hours after delivery, enabling immediate re‑breeding.
- Maximum reproductive output: a single female can produce 5–7 litters per year, equating to 30–80 offspring annually under optimal conditions.
Factors influencing these numbers include diet quality, housing density, stress level, and genetic background. Adequate protein (≈20 % of diet) and minimal crowding enhance both frequency of breeding and litter size, whereas poor nutrition or high stress reduce them markedly.