How do domestic mice reproduce? - briefly
Domestic mice breed year‑round, with females entering estrus every 4–5 days, mating quickly and delivering litters of 5–12 pups after a 19–21‑day gestation. The young become sexually mature at roughly six weeks, enabling swift population expansion.
How do domestic mice reproduce? - in detail
Domestic mice reach sexual maturity at 5–6 weeks for females and 6–8 weeks for males. Females display an estrous cycle lasting 4–5 days; proestrus and estrus together last about 12 hours, during which they emit pheromones that attract males. Mating occurs when a male mounts the receptive female, grasps the neck with his forepaws, and intromits. Copulation typically lasts 3–5 minutes, and a single encounter can result in successful fertilization.
After insemination, the gestation period averages 19–21 days. Embryonic development proceeds rapidly: implantation occurs around day 4, organogenesis by day 10, and fetal growth accelerates during the final week. Litters contain 4–8 pups on average, though numbers can range from 2 to 12 depending on strain, nutrition, and parity. Newborns are altricial, hairless, blind, and weigh 1–2 grams.
Pup care follows a strict schedule. The dam nurses continuously for the first 10 days, providing colostrum rich in immunoglobulins. By day 3, pups begin to develop whiskers; ear unfolding and fur growth start around day 7. Weaning occurs between days 21 and 28, after which juveniles become independent. Females can become pregnant again within 24 hours of giving birth, enabling a potential 5–7 litters per year under optimal conditions.
Key factors influencing reproductive efficiency include:
- Nutrition: High‑protein diets (18–20 % protein) enhance litter size and pup survival.
- Environmental conditions: Temperature of 20–24 °C and a 12 h light/12 h dark cycle promote regular estrous cycles.
- Genetics: Inbred strains may exhibit reduced fertility compared with outbred lines.
- Health status: Absence of pathogens and parasites is essential for normal mating behavior and gestation.
Understanding these physiological and environmental parameters allows precise management of breeding colonies and maximizes reproductive output.