How long does a mouse give birth? - briefly
A mouse’s gestation period lasts approximately 19–21 days from conception to delivery.
How long does a mouse give birth? - in detail
The gestation period of a common laboratory mouse (Mus musculus) averages 19–21 days from conception to parturition. This interval is relatively constant across strains, with minor variations of ±1 day influenced by environmental temperature, nutrition, and maternal age.
Key factors affecting the length of pregnancy include:
- Strain genetics – hybrid or outbred lines may exhibit slightly longer or shorter gestations compared with inbred strains.
- Ambient temperature – temperatures below 20 °C tend to prolong gestation, while optimal housing at 22–24 °C maintains the standard duration.
- Maternal condition – underweight or overly stressed females can experience delayed parturition; well‑conditioned adults typically follow the 19‑21 day schedule.
- Parity – first‑time (nulliparous) females often have a marginally longer gestation than experienced breeders.
Mice are induced ovulators; ovulation occurs shortly after mating, and implantation follows within 4–5 days. Embryonic development proceeds rapidly, with fetal organogenesis completing by day 14. By day 16–17, fetal movements are detectable, and by day 19 the pups are ready for delivery.
Litters range from 5 to 12 pups, with larger numbers correlated with slightly shorter gestational intervals due to uterine capacity constraints. After birth, the neonates are altricial, requiring maternal care for the first 2–3 weeks before weaning.
In summary, a mouse carries its young for roughly three weeks, with precise timing governed by genetics, environment, and maternal health.