How many pups are born to a mouse? - briefly
A female mouse usually gives birth to 5–10 young per litter, averaging around 6–8 pups.
How many pups are born to a mouse? - in detail
The average litter produced by a common laboratory mouse (Mus musculus) contains between five and eight offspring. Wild house mice typically have litters ranging from three to twelve, with most falling in the six‑to‑nine range. Litter size varies according to several biological and environmental factors:
- Genetic strain: Inbred laboratory strains such as C57BL/6 tend toward smaller litters (4‑6 pups), whereas outbred or hybrid strains often exceed eight.
- Maternal age: Young females (first estrous cycle) may deliver fewer pups, while mature breeders reach peak productivity around 4‑6 months of age.
- Nutrition and body condition: Adequate protein and caloric intake correlate with larger litters; undernutrition reduces both size and viability.
- Season and photoperiod: In temperate regions, increased daylight length during spring and summer promotes higher reproductive output.
- Parity: Second and third pregnancies usually yield larger litters than the first, after which litter size may decline with age.
Gestation lasts approximately 19–21 days. After birth, neonates are altricial, weighing 1–2 grams and remaining blind and hairless for the first week. Litter size directly influences neonatal mortality: larger litters experience higher competition for milk, leading to increased pre‑weaning deaths, whereas very small litters may suffer from insufficient stimulation of maternal care.
In summary, a mouse typically gives birth to a handful of young, most commonly six to eight, with the exact number shaped by genetics, maternal health, environmental conditions, and reproductive history.