Infant mortality is often high among ruffed lemurs, but can also be highly variable. In some seasons, as many as 65% are unable to reach three months of age, possibly due to falls and related injuries, although in some seasons infant mortality is as low as 0%. For those that do survive to adulthood, sexual maturity is attained at 18 to 20 months in females and 32 to 48 months in males. Sexual maturity may take longer to reach in the wild compared to captivity. For females, the inter-birth interval, or time between successive offspring, is typically one year, and in captivity, females can remain reproductively active until the age of 23. The life expectancy for both species of ruffed lemur is estimated at 36 years in captivity.