How many offspring does a gray mouse have at one time? - briefly
Gray house mice usually produce litters of five to eight young, with occasional extremes reaching twelve. Litter size varies with nutrition, age and environmental conditions.
How many offspring does a gray mouse have at one time? - in detail
The gray mouse typically produces a litter of six to eight young per birth, with observed extremes ranging from three to fourteen. Average litter size in laboratory strains centers around seven pups, while wild populations often show slightly lower numbers due to environmental pressures.
Factors influencing the number of offspring include:
- Age of the dam: First-time mothers usually have smaller litters; peak productivity occurs between 3 and 6 months of age.
- Nutritional status: Adequate protein and energy intake correlate with larger litters; deficiencies reduce fetal survival.
- Genetic strain: Inbred laboratory lines such as C57BL/6 yield consistent litter sizes, whereas outbred or wild‑type mice display greater variability.
- Season and daylight: Longer daylight periods stimulate reproductive hormones, modestly increasing litter size in wild specimens.
Gestation lasts approximately 19 to 21 days. After weaning at three weeks, a female can become pregnant again within 24 hours, allowing multiple litters per year. Under optimal laboratory conditions, a single female may produce up to five litters annually, resulting in a potential total offspring count of 30 to 40 per year.
These figures derive from extensive breeding records in both controlled research facilities and field studies of Mus musculus populations.