The Aldabra giant tortoise is believed to be a Vulnerable species, while several subspecies of the Galapagos tortoise are Vulnerable, Endangered, Critically Endangered, or completely Extinct. The last known Abington Island Tortoise, named Lonesome George, died in 2012.
Galapagos tortoises were used as food for whaling vessels sailing in the Pacific Ocean, and many tortoises were exported to California to use as food during the Gold Rush of 1849. As settlers moved to the Galapagos Islands, habitat clearance for cattle further harmed the tortoise populations.
The Aldabra tortoise, on the other hand, has benefited from a targeted conservation effort that goes back to the 1800s. A preserve was established back then to protect the tortoises and their habitat.