How old is a rat in human years?

Childhood and puberty

Compared to humans, rats have a brief, accelerated childhood. Rats develop rapidly during infancy and become sexually mature at about 6 weeks of age. Humans, on the other hand, develop slowly and don't hit puberty until about age 12-13 years (range: 8 to 16 years).

Adolescence and adulthood

Rats become sexually mature at age 6 weeks, but reach social maturity several months later at about 5 to 6 months of age (Adams and Boice 1983). In adulthood, each rat month is roughly equivalent to 2.5 human years (Ruth 1935).

Female rats enter menopause between ages 15 and 18 months (Durbin 1966), while humans enter menopause between 48 and 55 years (eMedicine).

Life expectancy

Domestic rats live about 2 to 3.5 years (Pass and Freeth 1993). In a survey of pet rat lifespans in the UK, the average lifespan was 21.6 months, and 95% percent had died by age 3 years (Clark 2004). In contrast, wild rats living in the wild tend to live for less than one year: 95% of wild rats die before age 1 year (Davis 1948).

The worldwide human life expectancy of humans is 66.7 years, but life expectancy varies a great deal between different countries. Human lifespan tends to correlate with economic development: people in the top 55 most developed nations have an average lifespan of 77.1 years, while people in the 33 least developed countries have an average lifespan of 49.4 years. In 2003, Japan had the highest life expectancy of 81.3 years, while Zambia had the lowest of 33.4 years (HD reports).

The rat's age in human years

Rat's age in months Rat's age in years Rat's age in human years 1.5 months (puberty) 0.125 years 12.5 years (puberty) 6 months (social maturity) 0.5 years 18 years (social maturity) 12 months 1 year 30 years 18 months 1.5 years 45 years 24 months 2 years 60 years 30 months 2.5 years 75 years 36 months 3 years 90 years 42 months 3.5 years 105 years 45 months 3.75 years 113 years 48 months 4 years 120 years