My species is the world’s largest mainland tortoise, easily reaching 30 inches (76 centimeters) in length and well over 100 pounds (45 kilograms) in weight. Some males even reach 200 pounds (90 kilograms)! We are surpassed only by the island dwelling tortoises from Aldabra and Galápagos in size and weight.
Turtles and tortoises are a very old group of reptiles, going back about 220 million years. Of all the animals with backbones, turtles are the only ones that also have a shell, made up of 59 to 61 bones covered by plates called scutes, which are made of keratin like our fingernails. The turtle cannot crawl out of it because the shell is permanently attached to the spine and the rib cage. The shell’s top is called the carapace, and the bottom is the plastron. Turtles can feel pressure and pain through their shells, just as you can feel pressure through your fingernails.
Given the sizzling hot climate where it lives—where days can reach 120 degrees Fahrenheit (49 degrees Celsius)—this tortoise digs dens up to 10 feet (3 meters) deep to recline in during the heat of the day. These underground havens are significantly cooler than the air above ground, dipping into the 70s (20s Celsius). These dens are often the only respite for other animals as well, so they reuse abandoned tortoise burrows.
The spur-thigh tortoise is most active during the rainy season between July and October. It is crepuscular in habit, meaning it leaves the den to forage at dawn and at dusk. It warms itself in the morning sun to raise its body temperature after the chill of night. The tortoise will become inactive during extreme temperatures and will hole up in an underground den.