Sulcata tortoises, also known as African spurred tortoises, can weigh, on average, 200 pounds and measure 24 to 36 inches long when fully grown, making them the third largest tortoise on Earth. Owners often want to know the sex of their sulcata tortoise, but because males and females look physically similar, determining a tortoise's gender can be difficult. Knowing how to spot the differences between males and females can help you identify the gender.
While young sulcata tortoises weighing less than 15 pounds and measuring less than 12 inches long are extremely difficult to sex, male and female sulcatas develop slightly different characteristics on the underbelly of their shell, also called the plastron, by adulthood. At the rear of the plastron are the anal scutes, a gap for the removal for urine and excrement and for access to reproductive organs. On female sulcatas this opening is very narrow, but on male sulcatas the opening is wider and flared.
Both male and female sulcatas are prone to aggressive behavior, but males are traditionally more aggressive, especially towards other male tortoises. A male will ram another male tortoise and attempt to flip him over in an effort to show dominance, sometimes causing serious injuries. In contrast, when females reach sexual maturity, their aggressive behavior tends to subside.
According to Sulcata Station, many sulcata owners are unsure whether their tortoise is a male or female until they witness their tortoise mounting another tortoise or laying eggs. Mating rituals begin with the male circling the female and sometime ramming her with his shell. The male will then mount the female tortoise. Absent any other distinguishable physical characteristics, observing these behaviors may be the only way owners can tell if their pet is male or female.
Pregnant females look and behave differently than male and nonpregnant female tortoises. Because a tortoise can lay up to 30 eggs at a time, a pregnant female's body will appear more swollen than normal. Pregnant females experience a decrease in appetite and become increasingly restless as nesting approaches. If you notice any of these changes or observe any of these behaviors, you may have a pregnant female tortoise.