Sterile Giant Tortoise Lawnmowers

STERILISING giant tortoises and setting them free on a precious eco-site may not sound like the ideal way to restore a Galapagos island to its former glory. But it's one that seems to be working on Pinta Island, the original home of famous giant tortoise "Lonesome George".


Conservationists freed 39 sterile tortoises on Pinta last May in the hope that they would regulate the native vegetation, which has returned with a vengeance ever since invasive goats were eradicated in 2003. The hope is that the tortoises will create clearings where native sun-loving plants can thrive. They had to be sterilised to ensure they wouldn't colonise the island, leaving it free for subsequent recolonisation with the Española tortoises most closely related to Lonesome George.


Vets this week described how they sterilised the 14 female tortoises sent to the island by removing their ovaries (The Veterinary Record, DOI: 10.1136/vr.c6520). The 25 males were sterilised by removing their phalluses, which are only used for mating.


The latest news from the island is that the tortoises were quick off the mark. "They immediately began eating the herbaceous plants, and the effects of their trampling have also been dramatic," James Gibbs, head of Project Pinta, told New Scientist. "They've had a big impact in a very short time." Gibbs and his colleagues will return to Pinta in May.



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