The Animal Itself
A large male Galápagos giant tortoise can weigh more than 400 kg and measure nearly two metres from the tip of its extended neck to the base of its shell. Females are considerably smaller, averaging 136–181 kg. The heaviest recorded individual was Goliath, a captive tortoise from Santa Cruz that reached 417 kg before his death in 2002.
The shell does more than protect the tortoise. It also helps regulate body temperature, heating and cooling slowly so the animal can conserve energy. A tortoise basking in the early morning sun can store enough heat to carry it through hours of slow grazing. This ability to conserve energy, combined with stored fat and fluid reserves, allows giant tortoises to survive for up to a year without food or water. Unfortunately, that same trait made them valuable as provisions for sailing ships, leading to thousands being taken aboard and removed from the islands.
Galápagos giant tortoises can live for 150 to 200 years, although determining the exact age of wild tortoises is difficult. Lonesome George, the last known Pinta Island tortoise, was estimated to be more than 100 years old when he died. A tortoise named Speed at the San Diego Zoo lived to an estimated 150 years. The true maximum lifespan remains unknown.
Their diet includes grasses, fallen fruit, cactus pads, and leaves. Their digestive system retains food for long periods, allowing seeds to pass through and be dispersed across the landscape, sometimes kilometres from where the tortoise originally fed. In this way, giant tortoises played an important role in spreading plants throughout the islands, even before they’d been named.
