How long does a mouse decompose under the floor? - briefly
A mouse carcass hidden under flooring typically fully decomposes within two to four weeks in warm, dry environments, but the process can extend to several months if the area remains cool and moist.
How long does a mouse decompose under the floor? - in detail
The rate of decay for a small rodent hidden beneath a floor depends on environmental conditions and the construction of the subfloor. Soft tissue typically breaks down within a few weeks, while the skeleton may persist for several months.
Temperature is the primary driver. At ambient indoor temperatures of 20 °C–25 °C, microbial activity and insect colonisation accelerate the process, reducing the soft‑tissue phase to 7–14 days. Cooler environments, such as basements maintained at 10 °C, can extend this period to 3–4 weeks. In cold storage below 5 °C, decay may be delayed for months, with the carcass remaining largely intact.
Moisture influences both microbial growth and insect development. High relative humidity (≥70 %) promotes rapid bacterial proliferation, shortening the soft‑tissue stage. Low humidity (≤30 %) slows decomposition and may lead to desiccation, preserving tissues longer.
Ventilation determines access for scavengers. A well‑ventilated crawl space allows flies and beetles to locate the carcass, introducing maggots that consume flesh within days. Poorly ventilated areas restrict insect entry, relying mainly on endogenous bacteria, which slows overall breakdown.
Floor material affects exposure. Wooden joists with gaps permit easier insect infiltration than solid concrete slabs, where only cracks or pipe penetrations provide access.
Typical timeline under average residential conditions (moderate temperature, moderate humidity, some ventilation, wooden subfloor):
- Days 1‑3: Early autolysis, bacterial activity begins.
- Days 4‑10: Insect colonisation, maggot mass develops, rapid soft‑tissue loss.
- Days 11‑21: Majority of flesh consumed, remaining tissues desiccate.
- Weeks 4‑8: Bones become visible, soft remnants disappear.
- Months 2‑6: Skeleton gradually disintegrates, depending on moisture and pH of surrounding material.
Variations outside these parameters can shift each phase proportionally. Forensic studies of rodent carcasses in controlled chambers confirm these ranges, highlighting temperature and humidity as the dominant factors.