Lifespan, longevity, and ageing
Maximum longevity: 90 years (captivity) Observations: Tuataras are the only living descendents from the Rhynchocephalia
order and thus have no closely-related species. They are found only in New Zealand. Even though tuataras rarely exceed one kilogram in weight, they are long-lived, attaining sexual maturity after 10-20 years and growing until they are 35-40 years. They probably live over 100 years (Castanet 1994). There is an anecdote of a male tuatara at the Southland Museum and Art Gallery first breeding when 111 years of age, but the age of this specimen is unverified. Tuataras appear to have a low optimal body temperature in comparison with other reptiles.