How many pups do mice give birth to at once? - briefly
A typical mouse litter consists of 5–12 newborns, with most domestic strains averaging 6–8. Wild house mice generally fall within the same range, although environmental conditions can cause variation.
How many pups do mice give birth to at once? - in detail
Mice typically produce litters containing 5 to 12 offspring, with the average number hovering around 7. The exact count varies according to species, genetic strain, age of the dam, and environmental conditions.
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Species differences:
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Strain influence: Laboratory strains such as C57BL/6 often yield 6‑8 pups, whereas outbred strains like CD‑1 can reach 10‑12.
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Maternal factors:
- First‑time females usually have smaller litters (4‑6).
- Females in their prime reproductive years (2‑8 months) produce the largest numbers.
- Advanced age reduces litter size and increases stillbirth risk.
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Environmental impact: Adequate nutrition, optimal temperature (20‑26 °C), and low stress correlate with higher pup counts. Poor diet or overcrowding can lower the number by 1‑3 pups.
Gestation lasts approximately 19‑21 days. After birth, pups are altricial, weighing 1‑2 grams, and rely on maternal milk for the first three weeks. Litter size directly affects growth rates; larger litters often result in slower individual weight gain due to competition for milk.
In summary, a typical mouse birth yields 5‑12 young, with the precise figure shaped by genetic background, maternal age, and husbandry conditions.