How long after mating do mice give birth? - briefly
Mice gestate for approximately 19–21 days, meaning they deliver litters roughly three weeks after copulation. Typical litters contain 5–8 offspring.
How long after mating do mice give birth? - in detail
Mice become pregnant shortly after successful copulation, which is usually confirmed by the presence of a vaginal plug within 24 hours. The embryonic development phase lasts about 19–21 days, depending on strain, nutrition, and ambient temperature. During this interval the fertilized eggs implant in the uterine lining, followed by rapid organogenesis and fetal growth. By day 14 the embryos are detectable by palpation, and by day 16 skeletal ossification is evident.
The final stage, parturition, typically occurs on the 19th to 21st day after mating. Labor begins with a series of uterine contractions, after which the dam delivers a litter ranging from 4 to 12 pups on average. Neonates are born hairless, blind, and dependent on maternal care for thermoregulation and nutrition. Within the first 24 hours the mother initiates nursing and grooming, essential for pup survival.
Key factors influencing the exact timing:
- Strain differences: Laboratory strains such as C57BL/6 show a mean gestation of 20 days, while outbred stocks may vary by ±1 day.
- Environmental temperature: Cooler environments can prolong gestation by up to 12 hours; excessive heat may shorten it slightly.
- Maternal age and health: Younger or undernourished females may experience delayed implantation, extending the period.
In summary, after successful mating, the interval before delivery is roughly three weeks, with minor variations attributable to genetic and environmental conditions.