Darwin’s tortoises

Charles Darwin (Google)

Charles Darwin
(Google)

While visiting the Galapagos archipelago in 1835, Charles Darwin (1809-1882) encountered the giant tortoise and observed that, as with the finches, each island had its own unique types of tortoise. The most notable difference, it turned out, was in the shape of the shell – some giant tortoises were able to extend their necks higher than others depending on what food source was available to them. They had evolved to survive on each particular island. The giant tortoise was a staple part of the diet of the indigenous peoples and also a source of money and goods from sale and trade – Darwin ate giant tortoise on James Island.

Forty eight specimens of giant tortoise were loaded onto the Beagle, but Darwin had yet to realise their significance to his fledgling theory of evolution – On the Origin of Species was not published until 1859 – and the tortoises were eaten and the shells, crucial to seeing the differences between the tortoises on each island, were thrown overboard.

Giant Galapagos Tortoise (Google images)

Giant Galapagos Tortoise
(Google images)

Two centuries of exploitation and unsustainable killing of the giant tortoise led to the loss of up to 200,000 tortoises, and by 1959 three of the originally identified populations were extinct with the remaining eleven groups seriously endangered. The establishment of the Galapagos National Park and the Charles Darwin Foundation, along with conservation efforts and captive breeding has seen the number of giant tortoises on the archipelago reach 20-25,000 today and there are currently fourteen species.

JJ