Sexing Tortoises

There are certain characteristics that most male tortoises share, but many species have a few that are unique to them. Please note: it is usually impossible to accurately sex a tortoise before it is sexually mature.

Shared characteristics

In most species of tortoises, the most common sexual characteristics are:

1. Size and color

– Male: Usually smaller and slightly more colorful than the females.
– Female: Usually larger to allow space for eggs.Usually somewhat more dully colored.
– The male impressed tortoise shows very distinctive color changes when mating.
– Red-footed Tortoises are one of the size exceptions- males are often larger at the
         same age.

2. Tails. One of the most helpful characteristics

– Males: Longer, with the cloacal opening in about the middle. May have a hardened claw-like tip in some species.
– Females: Very short and stubby, with the cloacal opening near the base.
– “Claw tips” are seen in Elongated Tortoises.

3. Carapace. In some species the shape of the carapace is distinctive

– Red-footed Tortoises in the northern parts of the range show a distinctive “wasp waist”.
– Male Hingeback Tortoises are more elongated than the rounder females.
– Male Hermann’s Tortoises are slightly wider at the rear than the female.

4. Plastron – Indent.  Another almost universal characteristic.

– Male: Mildly to deeply indented to allow them to better mount the female.
– Female: Flat or slightly bulging to allow more room for eggs.

5. Plastron — Gular Scutes

– Male: Some species have projecting gular scutes for fighting/flipping rival males.
– Female: Most species do not have projecting gulars.
– Some species with this characteristic include the Bowsprit, Plowshare and Desert Tortoises.

6. Plastron — Anal Scutes (Relevant for some species. See illustration below)

– Male: Anal scutes form a ‘wide’, open angle and the points are further from the marginals to allow the tail more freedom of movement.
– Female: Anal scutes form a tighter angle and the points are close to the marginals to allow more protection
– Some species with this characteristic are red-footed, star, Sulcata, Forstens, and Impressed Tortoises.

Screen Shot 2014-04-02 at 10.00.26 PMMale and female anal scute angles and gaps, courtesy of Vicente Niclos, Testudines.org

 

MTAIL22Adult male Brazilian Red-footed, note tail length and plastron indentation (photo thanks to ‘JD’)

This is slightly complicated by some research that shows that some long-term captive female Brazilian Red-footed Tortoises (and possibly some other species) show strongly masculine features and appear to be infertile.

Resources
Chelonia.org’s page of links for sexing other tortoise species

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