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Tortoises

Falling in the Class Reptilia, tortoises are from the Order Chelonia and are parallel to other Orders Crocodilia and Squamata, these being crocodiles and snakes and lizards respectively.

It is thought that tortoises lived long before the dinosaurs.

Our country is privileged to have the best tortoise diversity on earth, hosting 12 out of the 40 known species. In South Africa, the leopard tortoise (Stigmochelys pardalis) boasts the best range, this being the species most likely observed at Ingwelala.

Tortoises are divided into two sections, the carapace being the upper section and the plastron falling in below. An interesting fact is that whilst the land tortoises retract their heads horizontally into their shells, terrapins retract their heads sideways. Female tortoises have shorter tails than the males and shapes of carapaces and plastrons may also vary slightly between sexes. However, examples from fossils show that their shapes have not changed much over the past 200 million years – anyone for a nip and tuck?

The taste buds of tortoises are designed to be void of fussiness over food, and can therefore turn most plant matter into scrumptious meals that other herbivores tend to avoid, a well adapted feeding niche. Occasionally as a dietary additive, tortoises may find it necessary to ingest tiny invertebrates.

Female tortoises excavate earth cavities in which to lay their eggs, in some cases hatching can take up to 12 months. Survival rates are hazardously low. Conservation legislation therefore protects these reptiles. You may not kill, capture, donate, import or export tortoises, and so even keeping them as pets can only be done under special permits from local conservation authorities.

Many motorists feel it necessary to stop to assist tortoises crossing busy roads. Care should be exercised when uplifting and handling tortoises as they have a special water gland for storage which they absorb in times of uncertain water supply. Females also use this water to dampen soil when digging nesting holes. As a self defense mechanism, tortoises may excrete this water supply when being handled, and without an available water source to replenish it, such a tortoise may eventually die from dehydration.

In the wild tortoises are preyed on by larger birds such as ravens, ground hornbills and some predators. Other risks to populations are harvesting for human food source, loss of habitat through agriculture, hot veld fires, roads with high verges or curbs and electric fences with low strands that carry live voltage. Tortoises are very susceptible to overheating if overturned in the hot sun and unable to “right” itself

10 Fast Facts about tortoises:

  • They lack teeth
  • They are poor swimmers
  • Males will engage in combat (for space / breeding rights) with the objective of overturning each other
  • They use abandoned jackal and anteater burrows to assist in temperature regulation
  • In the wild, leopard tortoises may take as long as 15 years before reaching sexual maturity
  • They are most active when temperatures range between 25-39 degrees Celsius
  • No care is taken of the offspring
  • Shells are made of keratin, same as human nails and rhino horn
  • Sex determination in offspring is influenced by the environment, such as temperature and humidity
  • The largest species are found on the islands of Galapagos and Aldabra

NB: Many motorists feel it necessary to stop to assist tortoises crossing busy roads. Care should be exercised when uplifting and handling tortoises as they have a special water gland for storage which they absorb in times of uncertain water supply. Females also use this water to dampen soil when digging nesting holes. As a self defense mechanism, tortoises may excrete this water supply when being handled, and without an available water source to replenish it, such a tortoise may eventually die from dehydration. 

 

Facts researched from the internet, text by John Llewellyn.