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In South Africa’s west-coast Renosterveld region we searched for the highly endangered geometric tortoise (Psammobates geometricus) The early morning mist and cloud lifted and slowly rolled away to allow the Earth to be warmed by the sun.

One hour later we found a beautiful adult female of the species setting out to forage. This tortoise was believed to be extinct before its rediscovery in the 1960s.

The geometric tortoise is sometimes also called a ‘starred tortoise’, and is renowned for its striking shell or carapace, long sought after as an accessory. The shell is distinctively marked with beautiful yellow rays radiating outwards from central areolae.
No two individuals have the same markings on the carapace, each having a different number of rays in their ‘stars’, which provides an easy means of identifying different animals.

When threatened they immediately retract into their shell, which is actually an extension of the skeleton. Practically speaking, this creature has both an endoskeleton and an exoskeleton all in one … a remarkable physical defence adaptation.

Another interesting fact is that no tortoise has teeth! Both jaws are made of keratin, a horn-like material, and if you look carefully you can see that the beak-like upper jaw has a smooth cutting edge, while the lower jaw has a serrated cutting edge.

The external ear openings are covered with a thin tympanic membrane, but it is not certain exactly how well tortoises hear. Perhaps they respond to direct audio waves in the air or even to vibrations transmitted along the ground?

They do rely primarily on very good eyesight, and apparently also have a keen sense of smell. The weight and unwieldiness of the carapace greatly reduces the tortoise’s breathing capacity and the efficient movement of its blood, factors which generally slow the creature’s activities.

The average home range is somewhere between 1.5ha and 3ha (4-7 acres), which may be affected by vegetation density and food availability.

We also observed a smaller male geometric tortoise. The females are larger than the males and have a higher and more angled carapace.

These interesting little creatures are thought to be the oldest form of living reptile on Earth, and may be regarded as a remnant of pre-historic times.

On the timeline, they go back as far as 200-million years, and given that track record one might assume that they are guaranteed survivors, but that is not so. There are only an estimated 4 000 geometric tortoises on the planet and their habitat is both limited and threatened.

This video was filmed, edited and narrated by PAUL JOHN MYBURGH while working with Earth Touch in 2009*