PD Photo: A pair of tortoises mating in a zoo
Tortoises (land turtles) are reptiles living on land belonging to the family of Testudinidae of the order Testudines. Tortoises vary in size from a few centimeters to two meters. Their lifespan is compared to humans, though there are claims about tortoises in zoos/captivity having lived longer. For instance, in the Alipur Zoological Gardens in India there was an Aldabra Giant Tortoise brought to India by Lord Wellesley in 1875. It was at least 130 years old when it died, though there are claims that it was over 250 years old.
Many species of tortoises are sexually dimorphic. In some species, males have a longer, more protruding neck plate than females. In others the females’ claws are longer than males’ claws and females tend to be larger than males. The male also has a plastron that is curved inwards to aid mating.
Tortoises of some species lay only a single egg, while others may lay up to 30 eggs. For instance Testudo hermanni boettgeri, the Balkan Hermann's tortoise, lays 6 to 10 eggs. Most Mediterranean tortoises lay 5 to 6 eggs per clutch, and they can lay two or more clutches per season. Incubation of tortoise eggs depends on availability of favorable temperature range (around 30 °C), and for most species incubation takes between 8 and 11 weeks. The lower the temperature the longer it takes, for example, at around 27 °C incubation can take 18 weeks or more, while at 35 °C the mortality rate of eggs/newborn tortoises will be the highest.
