By Sid Perkins
An ancient volcanic eruption in the Galpagos Islands bequeathed diminished genetic diversity to one group of the archipelago’s famed giant tortoises, a new analysis suggests.
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Five subspecies of the Galpagos tortoise live on the island of Isabela, which is also home to five major volcanoes. Two of the subspecies live along Isabela’s southern coast and are now represented by only a few hundred tortoises each, says Luciano B. Beheregaray, a molecular ecologist at Macquarie University in Sydney, Australia. Those groups are the remnants of populations that were decimated by whalers and other seafarers who killed the creatures for food. Members of another subspecies, which escaped the stew pot by inhabiting the relatively inaccessible slopes of the island’s Alcedo volcano, number in the thousands.