One of the Galápagos tortoises that Dr. Charles Townsend had brought to the San Diego Zoo in 1933 was a full-sized adult male named Diego, from the island of Española. By the 1960s, the  tortoises of this island were declared critically endangered. The remaining 2 males and 12 females of the wild population were brought to the Charles Darwin Research Station in the Galápagos for protection. A search also took place, looking for tortoises from this island in zoos—which led to Diego. As one of only three remaining males, he could make a significant contribution to the conservation of his kind. The San Diego Zoo was glad to return him to his native land in 1977, where he joined his fellow Española tortoises at the Charles Darwin Research Station.

Diego soon proved his worth. He fathered several clutches of baby tortoises within a couple of years. And since then, you could say he has dedicated himself to the survival of his species. Estimates indicate he has about 1,700 offspring—and he’s still going strong today at the estimated age of 130!