This method of sexing a sulcata is not always exact. Sometimes a 10-inch sulcata will look like a female because its plastron is flat, then when the tortoise is about 12 inches in length, the plastron may change to concave.
When you purchase a baby sulcata, ask if it was temperature-sexed. Eggs incubated at temperatures above 89 degrees Fahrenheit most likely will be females.
Determining if a sulcata tortoise is a male or female takes a lot of patience -- about five years worth of patience. That is because both sexes look the same when they are hatchlings. Sulcatas are born with flat plastrons (bottom shells). As the tortoises grow to about 10 to 12 inches in length, their bottom shells and tails begin to change and tell the tale of their genders.
How to tell the gender of a baby sulcata tortoise
Turn the tortoise over onto its back.
Examine the plastron (bottom shell). The female's shell will be flat; the male's will be concave down near the tail.
Measure the anal scute, which is the part of the plastron just above the tail. The male will have a wider angle around the tail than a female.