| MadSci Network: Zoology |
This question is one which rarely supercedes the perenial query about age
of certain tortoises. The Kenyan tortoise here may be a giant Aldabran
tortoise, of which there are many in various zoos. This means we can age
and check reproduction of males. However the prime directive for many
zoologists is the production and care of the eggs. Females are therefore
studied, along with their fertility. Poor old males are stimulated electrically
and whether they would be able to produce sperm in the wild or not, active
sperm apparently appear from these middle-aged individuals around 130.
This brings us back to the reason for great age in certain animals. The big
answer is that tortoises metabolise very slowly and can survive without
oxygen for long periods. Each species must differ, especially if we compare
the carnivorous aquatic examples with the traditional vegetarian land
tortoise.
In the end the only conclusion can be that a large enough tortoise cares
little about age. "Lonely George", on the Galapagos island of Pinta survives
without possibly ever having met a female in his maturity. The search for a
possible mate from his own island or another island with almost matching
DNA is fascinating. What seems little in doubt is whether his actual age is
important in determining his virility. His sperm could be extracted by fair
means or foul, if a mate turns up.
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