How long do mice and rats live? - briefly
Mice usually survive 1–2 years, with some laboratory strains reaching about 3 years. Rats commonly live 2–3 years, and well‑cared pets can reach 4 years or longer.
How long do mice and rats live? - in detail
Mice typically reach adulthood within six weeks and live between 1.5 and 3 years under optimal conditions. Laboratory strains such as C57BL/6 often survive 2 – 2.5 years, while wild‑caught individuals rarely exceed 12 months due to predation and disease. Pet mice kept in stable environments may approach the upper limit of three years, provided they receive balanced nutrition, minimal stress, and regular veterinary care.
Rats display a longer lifespan than mice. Domestic varieties, including the common brown rat (Rattus norvegicus), generally survive 2 – 4 years, with some individuals reaching five years when housed in low‑density, enriched cages and fed a high‑quality diet. Laboratory strains such as Sprague‑Dawley average 2.5 – 3.5 years. Wild rats rarely live beyond one year because of environmental hazards.
Key factors influencing longevity for both species:
- Genetics: Inbred laboratory lines have predictable lifespans; hybrid or outbred populations show greater variation.
- Diet: Caloric restriction and high‑protein, low‑fat formulations extend life expectancy; obesity shortens it.
- Housing: Low‑density cages, bedding changes, and environmental enrichment reduce stress‑related mortality.
- Health management: Routine health checks, parasite control, and prompt treatment of respiratory or neoplastic diseases improve survival.
- Temperature and humidity: Stable ambient conditions (20‑24 °C, 40‑60 % humidity) prevent thermoregulatory stress.
Maximum recorded ages illustrate potential longevity: a pet mouse lived 4.2 years, and a laboratory rat reached 5.5 years. In contrast, average lifespans in wild populations remain significantly lower due to external pressures. Understanding these variables enables accurate predictions of rodent lifespan in research, pet care, and ecological studies.