Philadelphia Zoo Celebrates Birth Of Critically Endangered Tortoises
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On April 23, 2025, the Philadelphia Zoo introduced four female hatchlings of the critically endangered Western Santa Cruz Galápagos tortoises to the public. The new arrivals were named Dorothy, Rose, Blanche, and Sophia — after characters from the iconic television series The Golden Girls. They are the first of their kind to be born at the zoo in its 150-year history. Prior to this, there were only 44 Western Santa Cruz tortoises in US zoos, including three at Philadelphia.
The tortoises are the offspring of two of the Zoo’s most senior residents, Mommy and Abrazzo, both nearly a century old. Mommy is also the oldest-known first-time mother of her species. Fittingly, the hatchlings made their public debut on the 93rd anniversary of her arrival at the Zoo.
"Mommy arrived at the Zoo in 1932, meaning anyone that has visited the Zoo for the last 92 years has likely seen her. Philadelphia Zoo’s vision is that those hatchlings will be a part of a thriving population of Galapagos tortoises on our healthy planet 100 years from now," said Zoo president & CEO Dr. Jo-Elle Mogerman.
Mommy weighed just 40 pounds (18 kg) when she arrived from the Galápagos Islands. Today, at around 97 years old, she tips the scales at 284 pounds (128.8 kg). She is considered to be one of the most “genetically valuable” tortoises since her origins can be traced back to her native habitat. Abrazzo, now 96, arrived at the Zoo in 2020 as part of a breeding program and was introduced to Mommy soon after.
Since 2023, Mommy laid three clutches of eggs, but none hatched. She finally had success with her fourth clutch of 16 eggs laid in November 2024. The gender of Galápagos tortoise hatchlings is determined by incubation temperature. To ensure a mix, Zoo staff set half the eggs below 81.86° F (27.7° C) to produce males and the other half above 88.8° F (31° C) to produce females. The first egg hatched on February 27, followed by three more. All four hatchlings so far are female.
The young tortoises will remain at the Zoo for at least five years. After that, researchers will decide whether to send them to the Galápagos Islands or other zoos. This will depend on whether there are suitable mates at another zoo. As for Mommy, she may live another 100 years — so more hatchlings could still be in her future!
Galápagos tortoises are the largest living species of tortoise. Males can reach 6 feet long (1.8 m) and weigh over 500 pounds (226 kg), while females average around 250 pounds (113 kg). Native to the Galápagos Islands, these gentle giants can live to be between 100 and 200 years old.
Once found in abundance, Galápagos tortoise populations have been decimated by habitat loss, overhunting, and the introduction of predators. Today, 13 species comprising about 20,000 individuals live on the islands. This is a big improvement from the 1970s, when only about 3,000 remained. One of the rarest is the Western Santa Cruz tortoise, with only around 3,400 living in the wild. It is no wonder that the addition of four hatchlings is such a cause for celebration.
Resources: Smithsonianmag.com, Philadelphiazoo.org
