There are very few records of the longevity of monitor lizards in captivity (Flower 1925, 1937, Snider & Bowler 1992, Bennett 1994) and virtually none of their lifespan in the wild. The record appears to be held by the Taronga Zoo in Sydney, where a Komodo dragon was kept for 24.5 years. The animal was adult when acquired, and a total lifespan of about 50 years has been predicted for this species (Auffenberg 1981). The Tel Aviv University Zoo maintained an adult desert monitor for 17 years, and estimated its age at death as at least 25 years. Other large monitors lizards are recorded as surviving for 20 years or more in captivity. Unfortunately there is much less information available on the lifespan of the dwarf monitor lizards. A female spotted tree goanna kept at the Basel Zoo in Switzerland was still laying eggs after 20 years in captivity (Bennett 1994b). Of course, the reported figures tend to be exceptions rather than the norm but they do indicate that a life expectancy of at least a decade is not unreasonable and that many specimens of both large and small species can live for at east twice as long. Monitor lizards therefore, although they do not attain the great ages recorded for crocodilians and chelonians, are amongst the most long lived of the squamates. Consideling that most species can attain sexual maturity within three years it can be seen that the reproductive potential of these animals is enormous and that females of the more prolific species may be able to produce more than 500 eggs in a lifetime. Unfortunately this potential has not yet been realised in captivity.
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