Maximum longevity: 60 years (captivity) Observations: Maximum longevity has been estimated to be around 60 years, which is plausible. Males appear to be longer-lived than females and attain sexual maturity at later ages (Ronald Nowak 1999). Pregnant females have been reported up to 55 years of age. The MRDT was calculated to be about 10 and the IMR 0.015 for females (Foote 2008). One wild born specimen was still alive in captivity at 37.8 years of age (Richard Weigl 2005).