The Kapama chelonians

On kapama we have three species of chelonians; the Speke’s hinged tortoise, the leopard tortoise and the Marsh terrapin.

The most elusive of the big 5, is ironically is the most common of the “small” five.

The Leopard tortoise (Stigmochelys pardalis) also known as the Mountain Tortoise is the most common and largest tortoise in Southern Africa. For a species to be considered the most common it usually means that its adaptive skills are the best suited for their surrounding environment, and are absolutely opportunistic.

Scientific names are given to all animals, plants etc. to avoid confusion of multiple countries common names. The scientific names are also very descriptive of the animal in question. The generic name Stigmochelys is a combination of two Greek words: stigma meaning “mark”, “spot” or “point” and “chelone” meaning tortoise. The specific name pardalis is from the Latin word “pardus” meaning leopard and refers to the leopard-like spots on the tortoise’s shell.

In actual fact they float, this is due to their buccal cavity and dome shaped shell permitting greater lung size which is inflated. The buccal cavity is usually used as a water reservoir, keeping them hydrated in even the harshest environments. After inflating their lungs and buccal cavity they can cross dams and rivers bobbing around like a bottle cork, this adds to the statement that they are the most widely distributed tortoise in Africa. It is said that a leopard tortoise can be submerged for up to 10 minutes.

“Thanks to its very large, but light, domed shell, the Aldabra giant tortoise floats even more impressively. In 2004 a tortoise washed ashore on the Tanzanian coast, having survived the long drift from Aldabra Atoll. The weak and starving tortoise was covered in barnacles, and must have been drifting at sea for a long time. The ability to float not only saved this individual, but also saved the species from extinction.”

An average leopard tortoise grows to a length of 500mm and weighs around 18kg. Very large examples found in Zoo’s around Southern Africa are between 700 and 800mm and weigh around 50kg. The African Leopard Tortoise typically lives 80 to 100 years.

A very long-lived animal, the leopard tortoise is seldom sexually mature until it is between the ages of 12 and 15 years. Leopard tortoises “court” by the male ramming the female. While mating, the male makes grunting vocalizations. After mating, the female lays a clutch consisting of between five and 18 eggs. This enormous tortoise (4th largest in the world) starts from an egg about the size of a golf ball.

Leopard tortoises do not dig other than to make nests in which to lay eggs, butt will sometimes be found in abandoned warthog and anteater burrows. They use these burrows to escape from veldt fires, and extreme weather conditions.

The skin and background colour is cream to yellow, and the carapace is marked with black blotches, spots or even dashes or stripes. Each individual is marked uniquely.

The other terrestrial shelled vertebrate to grace Kapama with its company is the Speke’s hinged tortoise (Kinixys spekii) , unlike the rounded dome of the Leopard tortoise the Speke’s has a longer, flattened carapace (top half of the shell).

This species is named after Captain John Hanning Speke (1827 – 1864), English explorer and discoverer of the source of the Nile river.

Most terrapins etc have a hinge at the front of the shell that closes up the front part of the shell to protect the head and front legs (that do most of the paddling or swimming). But in the case of the Speke’s with a well developed posterior hinge, which the movement is more prominent in females, the function is to open up the shell (rather than close) when she is laying her eggs. In this species the male also has a distinctively longer tail than the female.

A couple of interesting facts about tortoises in general:

A tortoise shell is actually an extension of the back vertebrae, so the old folk tale that a tortoise can climb out its shell is a fallacy. The image below shows the internal structure of a tortoise, take special note of the vertebrae extending into the protective shell.

The picture on the left indicates the Carapace (or top half of the shell) and the picture on the right indicates the plastron (or bottom half of the shell).

The plastron can be used for the determining of sexes. Females possess a flat plastron, yet males have a more concave one. This function is for copulation purposes.

The carapace is dived into sections or oscoots, the oscoots can be used to get a rough estimate of the age of a tortoise. Much like the year rings in a tree each oscoot shows the year rings of a tortoise.

There is still a mountain of information about our chelonian friends, but more about that next time.

Riaan Bezuidenhout – Kapama River lodge
05/03/2013

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