When is the breeding period for mice? - briefly
Mice breed continuously under suitable temperature and nutrition, with activity peaking in spring and early summer. Gestation lasts 19‑21 days, enabling multiple litters each year.
When is the breeding period for mice? - in detail
Mice reproduce primarily during the warm months when daylight length exceeds ten hours. In temperate regions, the breeding season begins in early spring (March–April) and continues through late summer (August–September). Peak fertility occurs when ambient temperature ranges from 20 °C to 26 °C and food supplies are abundant.
Key physiological factors:
- Photoperiod: Longer days trigger the hypothalamic–pituitary–gonadal axis, increasing luteinizing hormone secretion.
- Temperature: Optimal reproductive performance is observed between 20 °C and 26 °C; lower or higher temperatures suppress estrus cycles.
- Estrous cycle: Female mice cycle every 4–5 days; each cycle includes proestrus, estrus, metestrus, and diestrus phases. Ovulation occurs during estrus, allowing conception if a male is present.
- Gestation: Approximately 19–21 days; litters of 5–10 pups are typical.
- Post‑partum estrus: Females can become receptive within 24 hours after giving birth, enabling rapid successive litters.
In laboratory environments, continuous breeding can be sustained year‑round if artificial lighting (14–16 hours light) and stable temperatures (22 °C ± 2 °C) are maintained, eliminating the natural seasonal constraints. Wild populations, however, remain restricted to the described seasonal window, with breeding activity diminishing sharply as days shorten and temperatures fall.