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Sexing Tortoises

There are certain characteristics that most male tortoises share, but many species have a few that are unique to them. Please note that 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. (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.
Differences between female and male red-footed tortoises
Male and female anal scute angles and gaps, courtesy of Vicente Niclos, Testudines.org


Adult 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


Edited 4-2-2013 (C) Mark Adkins

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