Diego, a Hood Island giant tortoise, is a symbol of hope for conservationists.
Believed to have hatched on Española Island in the Galápagos, Diego was taken from his native habitat as a young adult and shipped to the United States.
He spent years on exhibit in American zoos, including the San Diego Zoo, where his species remained unidentified until decades later.
In 1976, with his kind on the brink of extinction — only 15 Hood Island tortoises were known to exist — Diego became a key figure in a critical breeding program.
His contribution to the program resulted in over 900 offspring and helped restore the species’ population to more than 2,000 individuals.
After the program concluded in January 2020, Diego was retired and released back into the wild in June of the same year.
From Española to America
Diego is thought to have been born on Española Island sometime before 1920.
Between 1928 and 1933, he was captured and transported to the United States as part of a shipment of Galápagos tortoises destined for American zoos.
By the late 1940s, Diego had settled at the San Diego Zoo, though his specific subspecies remained unknown for years.
The Breeding Program
By the 1960s, the Hood Island giant tortoise (Chelonoidis niger hoodensis) was critically endangered due to overhunting and competition with invasive species like goats.
A breeding initiative was launched in 1976 to rescue the species.
At the time, only 12 females and 3 males remained on Española Island.
As only two of the males were suitable for reproduction, efforts expanded to locate other Española tortoises in captivity.
Diego, by then a long-term resident of the San Diego Zoo, underwent DNA testing, which confirmed his identity as a Hood Island tortoise.
In 1977, he was transported to Santa Cruz Island in the Galápagos to join the program.
Breeding pens were established, and juvenile tortoises were reintroduced to Española Island once or twice annually.
About half of these juveniles survived to adulthood.
During his time in the program, Diego fathered approximately 900 offspring — around 40% of all the juveniles produced.
Another male tortoise, referred to as E5, contributed to most of the remaining offspring, while a third, E3, was far less prolific.
Despite E5’s higher reproductive success, Diego became the star of the program, celebrated for his energetic and vocal mating behavior, which made him a favorite among the female tortoises.
Retirement and Return to the Wild
After decades of success, the breeding program concluded in January 2020, as the Española tortoise population reached 2,000 — a number deemed self-sufficient.
Diego, alongside 14 other tortoises, was released back onto Española Island on June 15, 2020.
At the time of his release, Diego weighed 80 kilograms (180 pounds), measured 90 centimeters (35 inches) in length, and could stretch up to 1.5 meters (4.9 feet) in height.
Experts estimate that Diego, now over a century old, may live to be 150.
Diego’s extraordinary journey from captivity to conservation icon underscores the power of focused efforts in saving species on the brink of extinction.
His legacy lives on in the thriving population of Hood Island tortoises that now roam Española, ensuring his story will endure for generations to come.
