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- The sex of a Galápagos tortoise is not resolute at fertilization but rather by the temperature at which its egg incubates.
- specifically, eggs incubated at or below 82.4 degrees Fahrenheit tend to hatch as female tortoises.
- These giant herbivores, native to the Galápagos Islands off Ecuador, lay up to 20 eggs at a time.
Galápagos Tortoise Sex Linked to Incubation Temperature
Updated June 18, 2025
The sex of a Galápagos tortoise is not resolute at fertilization but rather by the temperature at which its egg incubates. According to the Philadelphia Zoo, cooler temperatures yield females, while warmer temperatures produce males.
specifically, eggs incubated at or below 82.4 degrees Fahrenheit tend to hatch as female tortoises. Conversely, temperatures exceeding 85.1 degrees Fahrenheit typically result in male offspring.
These giant herbivores, native to the Galápagos Islands off Ecuador, lay up to 20 eggs at a time. The eggs, roughly the size of billiard balls, take four to eight months to hatch.
Galápagos tortoises are known for thier impressive size and longevity. Males can reach an average weight of 500 pounds, while females typically weigh around 250 pounds. In both zoos and their natural habitat, these reptiles can live for 100 to 200 years.