How many pups are born to a Japanese mouse? - briefly
Japanese mice usually produce litters of four to seven offspring, with an average of about five pups per birth. This range reflects typical reproductive output for the species.
How many pups are born to a Japanese mouse? - in detail
The Japanese mouse (Mus musculus molossinus) typically produces litters ranging from three to eight pups. In laboratory colonies, the mean litter size is about five, while wild populations show a broader distribution (3–8) depending on environmental conditions.
Key factors influencing offspring count:
- Seasonality – Breeding peaks in spring and autumn; litters in these periods often contain more young than those in winter.
- Maternal age – First‑time breeders usually have smaller litters (3–4); experienced females commonly reach the upper range (6–8).
- Nutrition – Access to high‑quality protein and energy sources correlates with larger litters; scarcity can reduce numbers to the lower end of the spectrum.
- Population density – High density may induce stress, leading to reduced litter sizes, whereas moderate density supports optimal reproductive output.
In captivity, controlled temperature (22 °C ± 2) and ad libitum feeding maintain the average of five pups per litter, with a standard deviation of roughly 0.9. Wild specimens exhibit greater variability, reflecting fluctuating food availability and predator pressure.
Overall, a Japanese mouse generally gives birth to between three and eight young per reproductive event, with five being the most frequent count under stable conditions.