Indian / Sri Lankan & Burmese Star Tortoises
Male vs female
Female Sri Lankan Star - notice the short, stubby tail
Male or female?
Determining the gender of young Star tortoises is not always straightforward because most of the gender characteristics apply to subadult and adult tortoises only. Burmese Star tortoises can be especially tricky to sex when young. Some young males can look more like girls for quite a while.
Very young male Star tortoises have flat plastrons and short tails, but the tail will grow and the plastron will concave as the male grows and matures. Some male youngsters start out looking more like females and then suddenly grow a big tail.
Some subadult individuals are easily sexed because one or more of the sex characteristics is quite obvious. With others, figuring out the gender is more difficult due to ambivalent sex traits. In those cases, you'll need to consider all the attributes as a whole.
Gender traits in adult Star tortoises
1. Size -- Females grow much larger than males.
2. Shape -- Females are typically more rounded in overall shape, while males are more elongated. Male tortoises can also have more flattened shells.
3. Plastron -- Females have flat plastrons and adult males have concave plastrons. Male's concave plastron aids in mating. As youngsters, both sexes have flat plastrons.
4. Tail -- Females have short, stubby tails. Males have bigger and longer tails. This is the most noticeable gender characteristic in adult tortoises. As youngsters, both sexes can have short tails.
5. Angle of anal scutes -- In males, it's very open with a wider angle. In females, the angle is narrower, and the opening may be more roundish to allow passage of eggs. In adult females, the tips of the anal scutes tend to point towards the back and in adult males more towards the sides. However, the shape of the anal scutes varies from individual to individual and can change in the same tortoise as it matures.
6. Growth rate -- Among siblings raised together, females may grow faster than males.
7. Flashing -- Many Indian Star tortoise boys start to "flash," i.e., show their private parts, in a warm bath when they reach the weight of 200-300 g. This is often the first sure sign that you have a male. :O)
Ps. For reference, see the shell scute diagrams.
Rules of thumb for sexing tortoises
- If the tortoise looks like a boy, it's a boy.
- If the tortoise looks like a girl, it could be a girl or a boy.
Subadult & adult tortoises:
- If the tortoise flashes, you know for sure you have a boy.
- If the tortoise lays eggs, you know for sure you have a girl.
Simple, right? :O)
Adult female Star tortoise
Adult Indian / Sri Lankan Star tortoise (Geochelone elegans) females have short, fat, stubby tails with a little tip. Angle of the anal scutes is narrower than in males, and the bony opening is often roundish to allow the passage of eggs. The supracaudal scute does not curve down, but opens up (for egg laying). The cloacal opening in the tail is roundish, looking kinda like a round star.
Adult male Star tortoise
Adult Indian / Sri Lankan Star tortoise (Geochelone elegans) males have long, thick, deep v-shaped tails. Anal scutes can be shaped like a mustache with the tips pointing towards the sides. The supracaudal scute typically turns inwards in adult males. Assumably, to protect the tail and male organ. The cloacal opening looks more like a slit towards the tail.
Note: The direction of the supracaudal scute varies among individual tortoises and different species. For example, in my Golden Greeks, both males and females have supracaudal scutes that open up. On the other hand, in my Angulate tortoises, both males and females have supracaudal scutes that turn under.
Examples - G. elegans females
The tail is short in females
Female G. elegans
Examples - G. elegans males
The tail is big and long in males
Male - notice the long length of the tail
Male - notice the inward curve of the supracaudal scute
Adult male Star tortoise's concave plastron. Photo courtesy of Jitka.
Photos of a G. elegans pair
Female Geochelone elegans may grow 2-3 times the size of a male!
Geochelone elegans pair - notice the size difference
Flashing vs prolapse
Young male Indian Star tortoises often "flash," i.e., show their private parts, in a warm bath. This is often the first sure sign that you have a male. The tortoise male part is sometimes described as looking like a purple flower or the Starship Enterprise. :O)
Many new tortoise owners become alarmed when they see their male tortoise "flash" for the first time. They often think there's something terribly wrong with the tortoise (e.g. an intestinal prolapse).
As long as the private part goes back in after a short while, everything is ok. If it prolapses and stays out, take your tortoise to the vet ASAP to have it treated. Otherwise, it may become necrotic and have to be amputated.
On a rare occasion, you may catch a glimpse of your female's private parts as well. The female part looks similar to a male's, but it's much smaller and doesn't have a long stem. More likely though, it's probably just a young, maturing male tortoise showing his immature bits. In boy tortoises, the bits start out small and then grow bigger as the tortoise matures.
Here's a link [Scientific American, offsite] to a science blog with photos of "flashing" male tortoises, including a male Geochelone elegans. WARNING: The photos are very graphic. NOT for small children.
For comparison, here's an article about intestinal prolapse with photos [Tortoise Trust, offsite]. Intestinal prolapse, or prolapse of any other internal parts, is an emergency.