Saddle-backed Rodrigues Giant Tortoise - Description and Evolution

Description and Evolution

The Saddle-backed Rodrigues tortoise was an exceptionally tall species of giant tortoise, with a long, raised neck and an upturned carapace, which gave it a giraffe-like body-shape almost similar to that of a Sauropod dinosaur.

It lived by browsing the taller vegetation, while its much smaller relative, the Domed Rodrigues giant tortoise, grazed on low vegetation such as fallen leaves and grasses.

The Saddle-backed tortoise was described by early colonists as a docile, gentle browser, with a tendency to gather in large herds, especially in the evening. An early Huguenot settler, in 1707, described the unusual group behaviour of these animals:
"There's one thing very odd among them; they always place sentinels, at some distance from the troop at the four corners of the camp, to which the sentinels turn their backs, and look with their eyes, as if they were on watch. This we have always observed of them; and this mystery seems the more difficult to be comprehended, for that these creatures are incapable to defend themselves..." (Leguat, 1707)

Both the Saddle-backed tortoise, and its smaller domed relative, were descended from an ancestral species on Mauritius (an ancestor of Cylindraspis inepta), which colonised Rodrigues by sea many millions of years ago, and then gradually differentiated into the two Rodrigues species.