Colours of Wildlife: Leopard Tortoise, Part 1
Created | Updated Sep 28, 2014
Leopard Tortoise
Willem is a wildlife artist based in South Africa. He says "My aim is simply to express the beauty and wonder that is in Nature, and to heighten people's appreciation of plants, animals and the wilderness. Not everything I paint is African! Though I've never been there, I'm also fascinated by Asia and I've done paintings of Asian rhinos and birds as well. I may in future do some of European, Australian and American species too. I'm fascinated by wild things from all over the world! I mainly paint in watercolours. . . but actually many media including 'digital' paintings with the computer!"
This is an African Leopard Tortoise, Stigmochelys pardalis. The scientific name means 'leopard-like marked tortoise'. It used to be put in the genus Geochelone along with some other very large tortoises, but now is recognized as the unique member of its own genus. This is the largest tortoise species in South Africa. Below you see a photo of a big one with my Dad, giving you some idea of its size. It can grow bigger still, although not quite as big as the giant tortoises found in the Seychelles and the Galapagos Islands; individuals reaching 70 cm/28" in length and 55 kg/120 lbs in weight are not unusual. Some can exceed a metre/yard in length, and this species is considered the fifth largest tortoise species in the world. Today all the really big tortoises are restricted to islands, but not so long ago, some occurred on the African mainland as well as in Asia and Australia. It is possible that humans eliminated all of these, so that only distant islands retained their giants. But some giant island tortoises were also exterminated, notably those that lived on the Mascarene Islands, Mauritius, Reunion and Rodrigues, and also a few local forms on some of the Galapagos Islands.
The leopard tortoise, though, is still fairly common and widespread. It lives in most of sub-Saharan Africa, except for Central and West Africa. In Afrikaans we call it a 'Bergskilpad' or 'Mountain Tortoise'. It is not at all restricted to mountainous regions, though, so the name is not really appropriate. But neither is the English common name. While young leopard tortoises have nice black specks and other markings on their brown shells, these fade with age and adult individuals may be entirely unmarked as you see in my photos. But young ones can be quite pretty and their markings vary so that no two individuals are alike. The Afrikaans name is also not entirely inappropriate, since this tortoise does often inhabit rocky terrain and is adept at climbing up steep slopes and sometimes even vertical surfaces. The curved claws at the tips of its feet give it an excellent grip.
Like other tortoises, this one can survive on very meagre resources, and thus does well in dry, semi-desert regions. But it is also found in moister environments. It munches all sorts of vegetation, but favouring grass and, in dry regions, succulents, the moisture in their leaves and stems helping it to survive with little access to surface water. This tortoise stores water in its body. When threatened it will eject this water … if you pick up a wild one, you may be surprised by the squirt of wetness and let it go.
Generally, leopard tortoises don't have much to fear … when they're big, that is. A big tortoise has a very hard shell, into which it retreats at the first sign of danger. This tortoise retracts its head fully into its shell and pulls its front legs in after it, closing up the front opening of the shell completely. As you see in the photo, the front legs have their outer surfaces covered in very big, hard, knobby scales. It pulls its hind legs in also. Even an adult lion or leopard can't do much with a tortoise in this state except for rolling it around. But unfortunately, tortoises don't start out big. A newly hatched leopard tortoise is only a bit over an inch in length, and at that point many things can gobble it up whole.
To insure that at least some of its progeny will survive, a leopard tortoise mum lays a clutch of up to 18 eggs all at once. She digs a hole in loose ground in which to lay them, and afterwards she covers them all up again with the soil. The little hatched tortoises dig themselves out, then scamper off to find their fortune. Most don't survive very long. They need to make it to the age of 12 to 15 to be sexually mature. But once mature, they can live for over a century.
At various stages in their lives, the tortoises would face different threats. As they grow bigger and their shells grow thicker, they have less and less to worry about. Eagles can pick them up and drop them on rocks from high up in the sky to crack their shells, but a tortoise that lives long enough will at last be too heavy for them to do this. But one predator on the African savannah can deal with them even when they're big. It is the Ground Hornbill. This formidable bird has a very hard and powerful beak. It can peck into a tortoise's shell, or into the front opening into which it withdraws its head and feet, and so kill and eat the tortoise.
Read on to learn more about the evolutionary story of the tortoise in Part 2 of this story.
