Classification and Range
Turtles are in the order Testudines and red-footed tortoises are in the family Testudinidae. These tortoises are further classified into the genus Geochelone, which includes a total of 11 species of tortoises. Some taxonomists classify red-footed tortoises in the genus Chelonoidis, as C. carbonaria.Red-footed tortoises live in southern Central America and throughout much of South America. Their range includes eastern Panama and west of the Andes in Colombia, but the main range is east of the Andes into eastern Colombia, Venezuela, Guyana, Suriname, French Guiana to eastern Brazil, south to Rio de Janeiro. From this point, their range extends westward to Paraguay, northern Argentina and eastern Bolivia. Red-footed tortoises are not prevalent in the western part of the Amazon Basin. They may occur naturally on Trinidad, and also live as an introduced species on quite a few Caribbean Islands.
Red-footed tortoises live in dry forest areas, grasslands and the savanna. They may also live in areas of rain forest that are close to open habitats. Red-footed tortoises share some of their range with yellow-footed tortoises; their ranges overlap in Suriname, where they both inhabit forests and grasslands.
Individuals have varying degrees of coloration, which varies according to locality of origin. Overall, the skin is mostly black. Like all turtles, the shell is divided into two halves: the top part (called the carapace) and the bottom part (called the plastron). The plastron and carapace are joined on each side by a “bridge.”
As with other species of tortoise, male red-footed tortoises have a concave plastron. For red-footed tortoises, the bumpy carapace is black, gray or brown. Small, distinct areas of yellow or tan coloring surround or cover each bump. There are several bright red marks or scales on its head and lower jaw. The legs and tail often have patches or individual scales that are orange, yellow or red. The plastron is dull yellow, brown, or black. The plastron may have some reddish tint or blurry dark marks along areas of recent shell growth”.
Length and Weight
Males are usually larger than females and grow up to 13.5 inches (34 cm) in length; females average 11.25 inches (29 cm) in length.
Red-footed tortoises have a life expectancy of about 50 years.
In the wild: red-footed tortoises are primarily herbivorous but also eat small amounts of animal matter, such as carrion. They also eat fungi, live and dead plants or fruits, flowers, soil, sand, and slow moving animals such as snails, worms and insects that they can capture.
At the zoo: fruits, vegetables and occasionally, commercial carnivore meat and dog chow.
Breeding occurs with the beginning of the rainy season. Males identify each other through a characteristic head movement that is a series of jerks away from and back to a middle position. If another tortoise is a male, he will make the same head movements. Males will battle each other, attempting to turn over one another.
However, there is not set territory to defend – they battle merely for the opportunity to mate with females. If the soliciting male receives a response of no head movement, this indicates that the other tortoise is a female. Scientific experiments and observation have shown that for mating to continue, both male and female must have “correct” coloration on the respective mate’s head. Then, the male sniffs the cloacal region of the female. Copulation usually follows the sniffing, but the male repeatedly circles the female and bites the legs of the female before mating.
During courtship and copulation, the male clucks in a set pattern of different pitches that sound very much like a chicken. The female excavates a nest in leaf litter and lays a clutch of five to 15 eggs from July to September. During the nesting season, she might lay several clutches. She does not incubate the eggs, so they must be well-disguised to avoid predators. The eggs have brittle shells and incubation lasts an average of 150 days, but can take as little as 105 days or as much as 202 days to hatch. As is the case with many reptiles, the eggs of red-footed tortoises are temperature sex dependent.
Incubation periods with temperatures above 88° Fahrenheit (31° C) result in the hatching of females. Incubation periods with temperatures below 82° Fahrenheit (28° C) result in the hatching of males. At incubation temperatures between these ranges, mixed sexes will hatch. Excessively high temperatures can cause lower hatch rates and deformed hatchlings. At birth, hatchlings are round, flat, 1.5 – 1.75 inches (39 – 45 mm) in length and weigh just 0.78 – 1.06 ounces (22 – 30 g).
Young hatchlings must find food quickly after birth, as they have little time to survive on the nutrients from their yolk or their time inside the egg. Like many other species of tortoises, red-footed tortoises grow slowly and do not become sexually mature until several years after hatching. As they grow older, red-footed tortoises gradually change color in the transition to adulthood. As juveniles, their carapace is pale yellow; but, as they mature, the carapace becomes dark brown or has more black patches.
Additionally, adult males show brighter colors on their legs and tail. Turtles and tortoises have hard, protective shells made up of 59 – 61 bones covered by plates (also called scutes). Like the bones of a human, a turtle’s shell is part of its skeleton. Contrary to myth, turtles cannot crawl out of their shell; it is permanently attached to their spine and rib cage. Just as humans can feel pressure on the bones or cartilage of their skeleton, turtles can feel pressure and pain through their shells. Commonly recognized as a defense strategy, turtles can pull their heads and legs inside their shells to varying degrees; some actually can fully close their shell (box turtles). In order for these extremities to fit inside the shell, a turtle may exhale air out of their lungs. Other turtles can barely pull any of their legs or heads into their shells and may protect their heads by tucking them sideways against the shell (side-neck turtles).
Turtles and tortoises do not have ears or hear like humans; they are not deaf and can respond to low frequencies. Instead, they depend on their other senses to help them find food or to avoid predators. To compensate, turtles and tortoises have an excellent sense of smell to help them find food. Additionally, turtles and tortoises don’t have teeth. Instead, the outside of their mouth has a hard, sharpened edge that the turtle uses to bite and chew. Red-footed tortoises are nomadic and follow available food sources. While searching for food, several other animals may capture and eat red-footed tortoises, such as foxes, dogs, lizards, rats and skunks.
Feet of Many Colors
The red-footed tortoise is one of three tortoises that are native to South America. The two other species are the Argentine tortoise (G. chilensis) and the yellow-footed tortoise (G. denticulata or Chelonoidis denticulata). The Argentine tortoise is easy to differentiate from the other two species, as it lacks much of the bright coloring found on the red-footed tortoise or the yellow-footed tortoise. However, it is a bit more difficult to distinguish the red-footed tortoise from the yellow-footed tortoise. Although both species share much of the same range and habitat, yellow-footed tortoises appear to prefer drier areas.
At first glance, a yellow-footed tortoise looks very similar to the red-footed tortoise. To the casual observer, the only different feature is the presence of yellow scales on the forelegs of the yellow-footed tortoise versus the red scales on the forelegs of the red-footed tortoise. However, of all the differences between these two species, the color of the scales on the forelegs is highly variable! Red-footed tortoises may have dull-colored, yellowish scales on their legs, while yellow-footed tortoises may have more brightly colored, reddish scales on their legs. From the top or front, the easiest way to identify the two species is by noting the scales on their heads. Yellow-footed tortoises have long scales on the top of their head close to the nostrils and the frontal scale is fragmented.
In contrast, red-footed tortoises have short prefrontal scales and the frontal scale is intact. Although yellow-footed tortoises usually grow to a much longer length, up to 26 inches (66 cm), this is not always a good way to distinguish species. Fortunately, there are also differences between the two species in the arrangement or appearance of scutes on the plastron and carapace. Additionally, the overall body shape of adult specimens is much different between yellow-footed tortoises and red-footed tortoises. Mature yellow-footed tortoises of both sexes tend to be wider, rounder and somewhat flatter in shape compared to female red-foot tortoises (that are longer) or the hourglass shape of male red-foot tortoises.
Terrapin, Tortoise or Turtle?
All of the reptiles in the order Testudines are classified as turtles. This order shows a great variety in size, from the (southern) spectacled padloper tortoise (Homopus signatus) that measures just 2.4 – 3.1 inches (6 - 8 cm) and weighs 5 ounces (140 g) when full grown, to the leatherback turtle (Dermochelys coriacea) that can grow to 9.8 feet (3 m) in length and weigh over 1,984 pounds (900 kg). Within the order Testudines, only a few species are actually called terrapins; however, researchers consider many of the animals in the family Testudinidae “true tortoises.” Unfortunately, people often interchange the terms “turtle,” “tortoise” and “terrapin.”
Depending on which country a person is in and due to colloquial differences in language throughout the world, any one of these terms may apply to a completely different type of species. Also, people usually choose a name for these animals based on the animal’s location and how it uses its habitat. For example, citizens of the U.S. commonly call turtles that live on land “tortoises”; turtles that live in or near freshwater areas are called “turtles”; and turtles that live in or near saltwater are called “terrapins” (this term is used less frequently).
In contrast, except for aquatic turtles, Australians call most of these animals “tortoises.” More confusingly, citizens of the United Kingdom refer to freshwater species as “terrapins” and saltwater species as “turtles.” There are certainly many differences and similarities between all species in Testudines. Generally, “turtles” are mostly aquatic (living in water) and this term especially applies to species that live in seas or oceans.
As a result, turtles tend to have webbed feet for swimming and a streamlined body shape. They also have either an omnivorous or herbivorous diet. In general, “tortoises” are primarily terrestrial (living on land) and have round, stumpy legs with no webbed feet. The shell of a tortoise is usually round or domed, bumpy and thick or heavy. Tortoises typically have an herbivorous diet. For “terrapins,” they are mostly semi-aquatic and live in saltwater or near swamps, rivers, ponds and lakes. Terrapins also have webbed feet for swimming and a smooth shell that is thinner than a tortoise’s shell. Many people also consider terrapins as the edible type of turtles.
Location at the Zoo
Woodland Park Zoo's red-footed tortoises are on display in the Day Exhibit. Zoo staff also use red-footed tortoises in various educational programs presented on zoo grounds. The zoo also keeps a number of other turtle and tortoise species off exhibit. Other species of turtles can be seen in the Day Exhibit, Trail of Adaptations and the aquatic exhibits in the award-winning Tropical Rain Forest. They include the yellow-spotted side-necked turtles, Egyptian tortoises and the black-breasted leaf turtle.
Red-footed tortoises are not an endangered species. However, they are protected under Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that they may not be exported from their home country without a permit. A listing on Appendix II means that they are not presently threatened with extinction but may become so if their populations are not monitored. Other species of tortoises in the family Testudinidae are not so fortunate, with at least 26 other species listed as either vulnerable, endangered or critically endangered.
The biggest threat to the survival of red-footed tortoises is overhunting by man. Since red-footed tortoises can survive for long periods of time without food and water, they are both easy and profitable to transport. Throughout much of their range, humans kill and eat thousands of red-footed tortoises, which are considered a delicacy in many cities of South America. An additional complication for their survival is that in underdeveloped areas, native people rely on their eggs as a major source of protein. The other threats to the survival of red-footed tortoises are loss of habitat and other human–caused activities. These activities include drainage of wetlands for agriculture, housing, logging and construction of roads. Turtles and tortoises are particularly vulnerable, since humans often develop the land next to lakes, rivers and seas where these animals come to lay their eggs. Due to their slow rate of growth and maturation, red-footed tortoise populations cannot maintain sustainable levels with the presence of these threats.
The increasing demand of the pet trade lowers numbers of many reptile populations to the point where they may become extinct in the wild. Every year, many more wild-caught animals die than ever reach pet stores. Those that survive are often stressed, malnourished and untamable. In recent years, humans have heavily imported many species of turtles and tortoises as increasing numbers of pet store owners want to sell them. One way to decrease demand for importation of reptiles is for potential owners to demand captive-born individuals. Red-footed tortoises, as all reptiles, play an important role in nature's web of life. Each of us needs to take action to protect wild habitats so turtles and all animals can continue to perform the vital roles they play in maintaining the delicate balance of nature.
Humans need red-footed tortoises and other reptiles
Here are only a few of the benefits they provide: Reptiles help keep prey populations in balance. Reptiles consume many animals that humans consider as pests, including mice, rats and destructive species of insects. This helps to control disease and damage to crops. Reptile venom and poison are used in medical research and provide effective medicines to fight certain human diseases.
Reptiles as Pets
We do not recommend reptiles as pets for most people as they require very specialized diets and environments. We also receive hundreds of requests each year to take former pet iguanas, boas and other reptiles but we cannot accept these due to space, health and unknown backgrounds. If you need to find a reptile or amphibian a new home, we suggest you contact a local herpetological group in your area.
In the Puget Sound region, contact the Pacific Northwest Herpetological Society as a resource. If you do choose to get a reptile as a pet, please learn as much as possible about their care and the best species before making your decision and never accept wild-caught animals as pets or release non-native reptiles or amphibians into the wild.
How You Can Help!
The effort to save endangered species requires cooperation and support at the international, national, regional and individual levels. You can help in this cause. Join and become active in Woodland Park Zoo and other conservation organizations of your choice. Please do not buy products made from wild animal parts. Contact your elected representatives and express your views about conservation of endangered species and wild habitats.
To learn other ways you can help, contact Woodland Park Zoo at email@example.com about supporting conservation programs at the zoo. Discover more about red-footed tortoises by contacting the Society for the Study of Amphibians and Reptiles at http://www.ssarherps.org, or the American Federation of Herpetoculture: AFH, PO Box 300067, Escondido, CA 92030-0067. Find other groups and information online at www.parcplace.org, the website of Partners in Amphibian and Reptile Conservation, or by searching the keyword "herpetology." Learn other ways you can help conserve wildlife and habitats by visiting our How You Can Help page.
Sources and Suggested Reading
Alderton, David. 2003. Turtles & Tortoises of the World. Facts on File, New York, NY. 191 p.
Bonin, Franck, Bernard Devaux and Alain Dupré. 2006. Turtles of the World. Johns Hopkins University Press, Baltimore, MD. 416 p.
Ernst, Carl H. and Roger W. Barbour. 1989. Turtles of the World. Smithsonian Institution Press, Washington, D.C. 313 p.
Halliday, Tim and Kraig Adler, eds. 1986. The Encyclopedia of Reptiles and Amphibians. Facts on File, New York, NY. 143 p.
Halliday, Tim and Mark O’Shea. 2002. Smithsonian Handbooks: Reptiles and Amphibians. Sagebrush Education Resources, Topeka, KS and Minneapolis, MN. 256 p.
Iverson, John B. 1992. A Revised Checklist with Distribution Maps of the Turtles of the World. Green Nature Books, Sumterville, FL. 400 p.
Pritchard, Peter C. H. 1979. Encyclopedia of Turtles. TFH Publications, Neptune, NJ. 895 p.
Pritchard, Peter C.H. and Pedro Trebbau. 1984. The Turtles of Venezuela. Society for the Study of Amphibians and Reptiles, part of Contributions to Herpetology series, Volume 2. Oxford, OH. 414 p.
Schwartz, Albert and Robert W. Henderson. 1991. Amphibians and Reptiles of the West Indies: Descriptions, Distribution, and Natural History. University Press of Florida, Gainesville, FL. 736 pp.
Vetter, Holger. 2005. Terralog: Turtles of the World Vol. 3: Central and South America. Edition Chimaira, Frankfurt, Germany. 127 p.
Obst, Fritz Jurgen. 1988. Turtles, Tortoises and Terrapins. St. Martins Press, New York, NY. 231 p.