How long is the gestation period of a house mouse? - briefly
The gestation of a domestic mouse lasts roughly 19–21 days, averaging about 20 days. This period is consistent across most laboratory and wild populations.
How long is the gestation period of a house mouse? - in detail
The pregnancy of a domestic mouse typically lasts between 19 and 21 days. Most laboratory strains, such as C57BL/6 and BALB/c, average 20 days from conception to birth. Wild‑caught individuals may show slightly longer intervals, up to 23 days, depending on environmental conditions.
Key factors that modify this interval include:
- Ambient temperature: Cooler environments (below 20 °C) can extend gestation by 1–2 days, while temperatures near 28 °C may shorten it.
- Maternal nutrition: Protein‑deficient diets increase gestational length and raise the risk of stillbirths.
- Parity: First‑time breeders often experience a marginally longer gestation (≈21 days) compared with experienced females (≈19 days).
- Strain genetics: Some inbred lines possess alleles that affect hormonal regulation, resulting in modest deviations from the 20‑day norm.
During the gestational period, embryonic development follows a rapid schedule:
- Days 0–3: Fertilization and implantation in the uterine lining.
- Days 4–7: Formation of the primitive streak and early organogenesis.
- Days 8–14: Differentiation of major organ systems; limb buds become visible.
- Days 15–20: Rapid growth of fetal tissues, maturation of the nervous system, and preparation for parturition.
Litter size correlates with gestational length; larger litters (7–10 pups) may slightly prolong the final days as uterine capacity is approached. Post‑delivery, the dam typically initiates a postpartum estrus within 12–24 hours, allowing a potential next conception as early as 4 days after birth.
In summary, the gestational duration for a house mouse is a narrowly defined window of roughly three weeks, with minor variations driven by temperature, diet, reproductive history, and genetic background.