When do mice give birth to pups? - briefly
Mice typically deliver their litters after a gestation period of 19–21 days, often during the night. The timing aligns with the species’ nocturnal activity pattern.
When do mice give birth to pups? - in detail
Mice reach reproductive maturity at 5–8 weeks of age. After successful mating, the gestation period lasts 19–21 days, with 20 days being the most common duration. Parturition therefore occurs roughly three weeks after copulation.
The estrous cycle of the common laboratory mouse spans 4–5 days. Ovulation occurs during the proestrus phase, and females are receptive to males for about 12 hours in estrus. Because the cycle repeats quickly, a female can conceive again within a week after giving birth, allowing multiple litters per year.
Litter size averages 6–8 pups but can range from 3 to 14 depending on strain, nutrition, and environmental conditions. Neonates are born altricial, hairless and blind, and they begin to gain weight rapidly. By day 10 they develop fur, and by day 14 they can be weaned.
Key timing points:
- Sexual maturity: 5–8 weeks.
- Estrous cycle: 4–5 days; receptive phase ≈12 hours.
- Gestation: 19–21 days (≈20 days typical).
- Post‑birth estrus: 1–2 days, enabling next conception.
- Litter weaning: 21 days.
Seasonal effects are minimal in controlled laboratory settings, but wild populations show increased breeding activity in spring and autumn when temperatures and food availability are optimal. Under stable conditions, a mouse can produce 5–10 litters annually.