When the Galápagos National Park began looking for Española giant tortoises in the mid-1960s, it found 12 females and two males. The species, Chelonoidis hoodensis, was about as close to extinction as an animal can get.
A third male turned up somewhere unexpected: the San Diego Zoo. Diego had been collected from Española in the mid-1930s and had lived in California for about 30 years. In 1977 he was sent to the breeding center on Santa Cruz Island in the Galápagos to join the program.
Forty years of work
Over the next four decades the program hatched and raised young tortoises and returned them to Española once they were large enough to survive. Nearly 1,900 juveniles were repatriated. Genetic testing later showed that Diego had fathered about 40 percent of them. Another male, known as E5, sired about 60 percent. The third male contributed very little.
A 2019 census found that the island’s population, now more than 2,300 tortoises, could sustain itself without further help. In January 2020 the program was closed. Galápagos Conservancy called it “one of the most successful captive reproduction and breeding programs ever undertaken anywhere in the world.”
The trip home for a Galápagos tortoise
On June 15, 2020, the 15 original breeders, 12 females and three males, were returned to Española. Each went through an extended quarantine and was fitted with a microchip. Then park staff carried them in.
“The 12 females, weighing an average of 77 lbs, were carried by a single person, while for the 3 males whose weight exceeded 120 lbs, two people were needed in relays,” said Danny Rueda, director of the Galápagos National Park. “After the release, the staff remained for approximately four more hours, making observations of the behavior of the tortoises as they settled back into their home.”
Each tortoise was fitted with a GPS device sending six positions a day, backed by 40 motion-triggered cameras spread across the release area. Diego was more than 100 years old at the time. He had been away from his island for roughly 85 years.
Sources
- Galápagos Conservancy, Española Tortoises Return Home Following Closure of Successful Breeding Program (June 2020)
- Smithsonian Magazine, Diego, the 100-Year-Old Tortoise Who Fathered 900 Babies, Returns to the Wild (Jan. 2020)
