1 June 2017
Room for more giants
By Sam Wong
Conservationists believe they can bring back a species of giant tortoise unique to Floreana Island in the Galapagos and considered extinct since the mid-19th century.
Galapagos giant tortoises are sometimes divided into 15 species, 11 of which survive today. The tortoise populations on all the islands were decimated after humans arrived in the archipelago and began loading them onto ships for their meat. They also brought animals such as rats, which can prey on young tortoises, and goats, which destroy their habitat.
Tortoises were eliminated from Floreana Island shortly after Charles Darwin’s visit in 1835. Another species, the Pinta Island tortoise, lost its last remaining member, named Lonesome George, in 2012.
But these species may not be gone forever. Both Floreana and Pinta tortoises have a saddle-shaped shell, allowing them to raise their necks to reach higher vegetation. In 2008, researchers discovered a few similar saddle-shelled tortoises living around Wolf volcano on Isabela Island, differing from the dome-shaped shell of most of the island’s tortoises. DNA collected from the saddle-shelled animals suggested they were descended from Floreana and Pinta Island tortoises.
It is thought that tortoises were moved between the islands on ships. Even though some mated with local tortoises and produced hybrids, the retention of a saddle shell by the tortoises around Wolf volcano raised the possibility of restoring the Floreana and Pinta species through captive breeding.
In 2015, scientists returned to Wolf volcano to look for more tortoises with Floreana and Pinta ancestry. They carried out blood tests on 144 individuals, then lifted 32 promising candidates onto a ship by helicopter and took them to a captive breeding centre on Santa Cruz Island.
Continued
Room for more giants
By Sam Wong
Conservationists believe they can bring back a species of giant tortoise unique to Floreana Island in the Galapagos and considered extinct since the mid-19th century.
Galapagos giant tortoises are sometimes divided into 15 species, 11 of which survive today. The tortoise populations on all the islands were decimated after humans arrived in the archipelago and began loading them onto ships for their meat. They also brought animals such as rats, which can prey on young tortoises, and goats, which destroy their habitat.
Tortoises were eliminated from Floreana Island shortly after Charles Darwin’s visit in 1835. Another species, the Pinta Island tortoise, lost its last remaining member, named Lonesome George, in 2012.
But these species may not be gone forever. Both Floreana and Pinta tortoises have a saddle-shaped shell, allowing them to raise their necks to reach higher vegetation. In 2008, researchers discovered a few similar saddle-shelled tortoises living around Wolf volcano on Isabela Island, differing from the dome-shaped shell of most of the island’s tortoises. DNA collected from the saddle-shelled animals suggested they were descended from Floreana and Pinta Island tortoises.
It is thought that tortoises were moved between the islands on ships. Even though some mated with local tortoises and produced hybrids, the retention of a saddle shell by the tortoises around Wolf volcano raised the possibility of restoring the Floreana and Pinta species through captive breeding.
In 2015, scientists returned to Wolf volcano to look for more tortoises with Floreana and Pinta ancestry. They carried out blood tests on 144 individuals, then lifted 32 promising candidates onto a ship by helicopter and took them to a captive breeding centre on Santa Cruz Island.
Continued
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