Introduction to a Remarkable Birth

Much like humans, some animals also delay parenthood. A remarkable example of this is a pair of Western Santa Cruz Galápagos tortoises residing at the Philadelphia Zoo, who have recently become parents as they approach their 100th year.

The Arrival of the Hatchlings

This month, the Philadelphia Zoo announced the successful hatching of four tortoises, born to the male tortoise Abrazzo and his mate, aptly named Mommy. This historic event marks the first time these tortoises have been born in the zoo’s 150-year history. Notably, Mommy is the oldest documented female of her species to become a mother. The possibility of more hatchlings emerging in the coming weeks is also anticipated.

Species Overview

Galápagos tortoises, named after their native habitat, the Galápagos Islands off Ecuador, are the largest tortoises worldwide, with a captive lifespan of over 170 years. The Western Santa Cruz Galápagos tortoises are one of the 13 living subspecies of these tortoises.

Conservation Status

The population of Galápagos tortoises began to decline steeply in the 19th century due to hunting and the introduction of invasive species. Although conservation efforts have helped increase their numbers, there are currently only about 20,000 of these tortoises in the wild. Specifically, the Western Santa Cruz tortoises are critically endangered, making the birth of these hatchlings particularly significant.

Video: A Glimpse into the Lives of Galápagos Tortoises

The Journey to Motherhood

Mommy has been a resident of the Philadelphia Zoo for over 90 years. In 2020, as part of the Association of Zoos and Aquariums’ (AZA) Species Survival Plan, the zoo brought in Abrazzo from Riverbanks Zoo and Garden in South Carolina, hoping he would mate with Mommy. This blind date was successful, and by 2023, Mommy started laying clutches of eggs.

Challenges and Success

Unfortunately, the first three clutches of eggs did not yield viable offspring. However, Mommy’s fourth clutch, laid in November 2024, was successful. The sex of Galápagos tortoises is determined by the incubation temperature of their eggs. Out of 16 eggs laid by Mommy, which were incubated at temperatures that could yield up to 8 males and females, four female hatchlings have emerged so far.

Reaction from the Zoo

Lauren Augustine, Director of Herpetology and Birds at the zoo, expressed the significance of this achievement, stating, "This is a monumental achievement for our animal care team who worked diligently to provide the right conditions for Mommy to lay her eggs and for the eggs to incubate and successfully hatch. This successful outcome comes from years of hard work studying animal behavior and providing top-level care. Until now, Mommy’s genes were not represented in the AZA population, making these offspring extremely important in the protection of this species."

Importance of the Hatchlings

These hatchlings are the first to be seen in an AZA-accredited zoo since 2019. With only 44 individual Western Santa Cruz Giant tortoises in all U.S. zoos combined, according to the Philadelphia Zoo, these new additions are vital for the continued conservation of this rare subspecies. Fortunately, Mommy’s contribution to the gene pool may not be over yet, as her first tortoise hatched on February 27, and the team is monitoring additional eggs that could hatch in the next few weeks.

Public Debut and Naming

The Philadelphia Zoo plans to introduce Mommy’s hatchlings to the public on April 23, marking the 93rd anniversary of her arrival at the zoo. They also intend to involve the public in naming these crucial new members of the tortoise family, ensuring their significance is recognized and celebrated.