Red-footed Tortoise - Description

Description

Red-footed tortoises show gender, regional and individual variations in color, shell shape, and minor anatomic characteristics. Adult red-footed tortoise carapaces are generally an elongated oval with sides that are nearly parallel, although the sides of males may curve inwards. They are fairly highly domed and smooth with a rather flat back. There is often a high point over the hips and a small sloped section over the neck. The vertebral and costal scutes (the scutes along the center and sides of the carapace) are black or dark brown with a pale yellow areole in the center. The marginals (scutes along the edge of the carapace) 'tuck under' along the sides and flare slightly over the limbs. They are dark with the pale aureole along the middle of the lower edge. The nuchal scute (the marginal over the neck) is absent, and the marginals over the tail are joined as one large supracaudal. Growth rings are clearly evident in most individuals but become worn smooth with age.

The plastron (bottom shell) is large and thick along the edges. The gulars (frontmost pair of plastron scutes) do not protrude much past the front of the carapace. The plastron of a male is deeply indented, and the anal scutes (rearmost pair of plastron scutes) may be used to sex the animal while the color pattern varies by region.

The head is relatively small with a squared-off profile and flat on top, longer than it is wide. The eye is large with a black iris, and rarely any sclera visible around it. The upper jaw is slightly hooked, and the upper jaw is notched in the front middle. There are fifteen to twenty 'teeth' or fine grooves on each side of each jaw. A nearly circular tympanum is located behind and below the eye and is covered with a dark scale. The scales of the head are generally smallish and irregular, becoming small and pebbly on the neck. Many of the scales are colored pale yellow to brick red, especially those on the top of the head, above the tympanum, around the nostrils, on the lower jaw, and on the sides of the neck. Males are usually slightly more colorful than females, and colors vary by region.

The limbs are generally cylindrical with four claws on the forelimbs and five on the hind, but no visible toes. The forelimbs are slightly flattened and the front surface is covered with large scales, mostly with the same color as the head. They are not as large or protrusive as they are in more primitive species such as the African spurred tortoise (Geochelone sulcata). The tail is muscular, varies in length and overall shape by gender, and lacks any sort of claw on the tip.

Average adult sizes vary by region and gender, and 'giants' are often encountered. Red-footed tortoises average 30–35 cm (12–14 in) with males slightly larger overall. Red-foots of up to 45 cm (18 in) are fairly common and over 50 cm (20 in) are occasionally discovered. The largest known specimen was from Paraguay, was 60 cm (24 in) long, and weighed over 28 kg (62 lb)! It is unknown if the 'giants' represent diet availability, genetic issues, longevity, or other possibilities.

Hatchling and young red-footed tortoises have much rounder and flatter carapaces that start off as mostly pale yellow to brown. New growth adds dark rings around the pale center to each scute. The marginals of very young red-footed tortoise are serrated, especially over the hind limbs. This probably aids in both camouflage against the leaf litter and in making the small animals harder to eat. Young tortoises are generally more colorful overall.