The Yellow-Footed Tortoise

Nov 15, 2009 Features / Columnists, Interesting Creatures in Guyana

---

According to Conservation International, Yellow-footed tortoises (Geochelone denticulata), also known as Wayamu, like to build their nests in the dense rain forest or in the tropical lowlands. Since they are too slow to capture fast animals, their diet consists of grasses, fallen fruit, carrion, plants, bones, mushrooms, excrement, and slow-moving animals such as snails and worms.
CI has also been able to establish that on average, a female will lay between 6–16 brittle-shelled eggs per year. Larger females produce a higher quantity of eggs and also lay larger eggs. The young are self-sufficient from birth.
The Yellow-footed Tortoise reaches maturity in between 8–10 years and can live for approximately 50–60 years. This species is considered threatened because it is heavily hunted for food and is sold in the international pet trade.
Several yellow head scales and a horizontal bar could be found behind a Yellow-footed tortoise’s eye. The carapace (shell top) is black with a small, distinct yellow area around the areola on each scute (shell scale). Adult males reach a length of up to 13.5 inches (30.4 cm) in length, while the maximum size of females is 11.25 inches (28.9 cm) in length.
Mature specimens have distinctive incurving of sides, giving them a well-defined “waist.” The plastron (shell bottom) is a relatively bland yellow-brown; there may be some reddish tint and vague dark marks along areas of more recent growth. The plastron is extremely concave in adult males. Consequently, the male is much lighter than the female. The female has a very flat plastron and short, stubby tail. There is quite a bit of variation in colouring, with the legs and head often having patches of orange, yellow or red. The skin is black with bright yellow marks on the head and lower jaw. Many of the scales on the limbs and tail are bright scarlet.
The Yellow-footed tortoise is found in extreme southern Central America, and central and northern South America including the countries of Panama, Colombia, Venezuela, Guyana, Suriname, French Guiana, Brazil, Bolivia, Paraguay, Argentina, and on several Caribbean islands.
These turtles make a sound like a baby cooing with a raspy voice. Tortoises also identify each other using body language. The male tortoise makes head movements toward other males, but the females do not make these head movements. Male tortoises also swing their heads back and forth in a continuous rhythm as a mating ritual. Mating occurs all year round for the Yellow Footed Tortoise. There is no parental care of the young and the baby tortoises will fend for themselves, starting by eating calcium rich vegetables.
This South American tortoise eats many kinds of foliage. They are too slow to capture any fast animals, as was noted earlier. In captivity, they are fed oranges, apples, bananas, hard-boiled eggs, kale, endive, collard greens, spinach, carrots, and alfalfa pellets. Each Yellow Footed Tortoise in the wild reaches the age of maturity at about 8-10 years.
The fecundity of a female generally depends on the size, the bigger they are, the more eggs they can produce. On average, a female will create approximately 6-16 eggs per year, although some female individuals may not reproduce each year. The eggs have brittle shells and are elongated to spherical, approximately 3-6 cm in diameter. The egg size will increase with the body size of the turtle. The young are self-sufficient from birth. They can live for approximately 50-60 years.
Breeding is synchronized with the onset of the rainy season, (from July to September) where a general increase in activity is noted. Males identify each other eliciting a characteristic head movement, a series of jerks away from and back to mid-position. Another male will make the same head movements. If he gets no head movement in response, it is the first indication that the other tortoise is a female. Scientific experimentation and observation has also indicated that the head coloration has to be correct. He will then sniff the cloacal region of the other tortoise. Copulation usually follows, though sometimes there is a period of biting at the legs. During courtship and copulation, the male makes clucking sounds that sound very much like a chicken. There is a set pattern in pitches of the clucking sounds. Rival males will battle, attempting to overturn each other, however neither the males or females will defend a territory. They are considered nomadic in their movements.
It is interesting to note than in almost every tortoise species where male combat occurs, the males are always larger than the females. This is in comparison to aquatic species, where the males are usually smaller than the females and do not engage in male to male combat. It is thought that species with male combat evolved larger males because larger males have a better chance of winning a bout and mating with a female, thus passing on their larger size to their offspring. Species with smaller males evolved because smaller males are more mobile and can mate with a large number of females, thus passing on their genes.
Geochelone denticulata is an endangered species. The major populations are located in South America, and they are protected under the Convention on International Trade in Endangered Species, also known as CITES. (Source: Wikipedia – The Free Online Encyclopedia)

---

---