Geographic Range
Red-footed tortoises (
Geochelone carbonaria
) has a broad geographic range east of the Andes that extends from eastern Columbia
through the Guianas, continuing south through eastern Brazil to Rio de Janeiro, and
west to Bolivia, Paraguay and northern Argentina. They appear to be absent from all
but the easternmost Amazon Basin. Red-footed tortoises are also native to Panama
and western Columbian on mainland South America, and the island of Trinidad in the
Caribbean. They have recently been introduced to other islands in the Caribbean.
- Biogeographic Regions
- neotropical
Habitat
Geochelone carbonaria
can be found in rainforests, dry thorny forests, temperate forests, and in savanna
areas. It prefers heavily forested, humid habitats but avoids muddy areas due to low
burrowing capacity of these habitats. This species is less common in forest clearings
associated with palms, mangoes, and other vegetation.
- Habitat Regions
- tropical
- terrestrial
- Terrestrial Biomes
- savanna or grassland
- forest
- rainforest
Physical Description
The carapace of red-footed tortoises ranges from dark-brown to blackish brown. Each
scute contains a pale center called the areolae. Outer regions of each scute are golden-brown,
and the edges tend to be dark-brown. The plastron can range from pale to a dark yellow,
and the scales on the limbs and tail are enlarged and can range from yellow to dark
reddish orange. Scales on the dorsal surface of the head have dark margins and are
bright in color. Parietal scales are the brightest on the head, and frontal scales
are typically more pale in comparison. Males are larger than females and have a more
obtuse posterior anal notch. Females have an acute or rounded posterior anal notch
and their xiphiplastron (the posterior-most scute) is not as heavily developed when
compared to males. In males, the posterior edge of the xiphiplastron tends to form
a thickened, nearly vertical free margin, whereas in females, it tends to be beveled
inward and upward. Adults can reach 510 mm in carapace length.
- Other Physical Features
- ectothermic
- heterothermic
- bilateral symmetry
- Sexual Dimorphism
- male larger
Development
At reproductive maturity,
Geochelone carbonaria
exhibits a central narrowing of the shell. In older individuals, the sides of the
carapace expand, especially in females, and the abdominofemoral region becomes indented
and slightly saddle-backed. The tail is longer and more distinct in males when compared
to females. Males have a small opening between the carapace and plastron, which allows
for movement of their heavier tail. Offspring sex is determined via ambient temperature
during development.
- Development - Life Cycle
- temperature sex determination
Reproduction
Geochelone carbonaria
is polygynous, and males produce sounds and calls associated with distinct gular
motions that are meant to attract potential mates and ward off competitors. Calls
consist of a series of “clucks”, similar to those produced by
chickens
. Males compete for mates, and typically move their heads in a bobbing motion prior
to wrestling. He who flips his competitor on his back gains access to the female and
an opportunity to mate.
- Mating System
- polygynous
Most red-footed tortoises become sexually mature by 200 to 250 mm in length, which
typically occurs around 5 years of age. They mate throughout the year in captivity,
but nesting occurs from June through September. Females may nest several times during
a season, depositing 2 to 15 eggs per clutch. Incubation times range from 117 to 158
days. Hatchlings have a carapace length ranging from 39 to 45 mm and weigh 22 to 30
g.
- Key Reproductive Features
- iteroparous
- year-round breeding
- gonochoric/gonochoristic/dioecious (sexes separate)
- sexual
- oviparous
- sperm-storing
In order to ensure successful egg production, female
Geochelone carbonaria
store substantial energy in the form of fat and sequester minerals in their bones
for the formation of the egg-shell. During egg development, they feed on a nutrient-rich
diet in order to maintain mineral deposits.
Geochelone carbonaria
lay their eggs in flask shaped nests that are about 20 cm deep in the ground. Prior
to oviposition, females become restless and search for a good nesting area. Once oviposited,
eggs are covered and there is no parental care. Hatchlings dig their way out of the
nest and are immediately independent.
- Parental Investment
-
pre-hatching/birth
-
provisioning
- female
-
provisioning
Lifespan/Longevity
There is no information available regarding the average lifespan of Geochelone carbonaria .
Behavior
Red-footed tortoises "gaze follow" conspecifics, which consists of gazing in the same
direction as conspecifics in the immediate area. They are diurnal and appear to avoid
moving great distances. Outside of their reproductive behavior, little else is known
of the general behavior of this species.
Home Range
There is no information available regarding the home range of red-footed tortoises.
Communication and Perception
Geochelone carbonaria
produces a series of clucks, which sound similar to those produced by domestic
chickens
. Clucks are primarily produced by males during courting or mating. Juveniles may
also cluck or chirp and produce these sounds on a regular basis while foraging. Prior
to clucking, juveniles stop foraging and bob their head while producing the sound.
Little else is known of communication and perception in this species.
- Communication Channels
- acoustic
- Perception Channels
- visual
Food Habits
Geochelone carbonaria
feeds primarily on fruit during the wet season and flowers during the dry season.
Throughout the year, they also consume dead and living foliage, soil, fungi, stems,
sand, pebbles, and carrion. Males consume greater amounts of fruit compared to females.
Geocehlone carbonaria
occasionally ingests sand, which has been hypothesized to act as an abrasive agent
enhancing digestion of plants materials.
- Animal Foods
- carrion
- Plant Foods
- leaves
- wood, bark, or stems
- fruit
- flowers
- Other Foods
- fungus
- detritus
Predation
Other than
humans
, there is no information available concerning predators specific to
Geochelone carbonaria
.
Ecosystem Roles
As frugivores, red-footed tortoises may be important dispersers of seeds of tropical
plants such as
figs
and
bromeliads
. One study found that viable seeds of both types of plants were found in the feces
of several red-footed tortoises in Brazil.
- Ecosystem Impact
- disperses seeds
Economic Importance for Humans: Positive
Red-footed tortoises are hunted for their meat throughout their geographic range.
- Positive Impacts
- food
Economic Importance for Humans: Negative
There are no known adverse effects of
G. carbonaria
on humans.
Conservation Status
Geochelone carbonaria
has not been evaluated by the International Union for Conservation of Nature (IUCN),
however, many island populations are likely in serious decline as habitat loss and
over hunting pose a serious threat throughout its geographic range.
Geochelone carbonaria
occurs in numerous wildlife reserves and national parks throughout its geographic
range. Without current population estimates, it is difficult to predict the potential
conservation and management needs for this species. The
Other Comments
Geochelone carbonaria
is also referred to as
Chelenoidis carbonaria
and
Testudo carbonaria
.
Additional Links
Contributors
Khushwant Kaur (author), Indiana University-Purdue University Fort Wayne, Mark Jordan (editor), Indiana University-Purdue University Fort Wayne, John Berini (editor), Animal Diversity Web Staff.
- Neotropical
-
living in the southern part of the New World. In other words, Central and South America.
- introduced
-
referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.
- native range
-
the area in which the animal is naturally found, the region in which it is endemic.
- tropical
-
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
- terrestrial
-
Living on the ground.
- tropical savanna and grassland
-
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
- savanna
-
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
- temperate grassland
-
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
- forest
-
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
- rainforest
-
rainforests, both temperate and tropical, are dominated by trees often forming a closed canopy with little light reaching the ground. Epiphytes and climbing plants are also abundant. Precipitation is typically not limiting, but may be somewhat seasonal.
- marsh
-
marshes are wetland areas often dominated by grasses and reeds.
- swamp
-
a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.
- ectothermic
-
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
- heterothermic
-
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
- bilateral symmetry
-
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
- polygynous
-
having more than one female as a mate at one time
- iteroparous
-
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
- year-round breeding
-
breeding takes place throughout the year
- sexual
-
reproduction that includes combining the genetic contribution of two individuals, a male and a female
- oviparous
-
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
- sperm-storing
-
mature spermatozoa are stored by females following copulation. Male sperm storage also occurs, as sperm are retained in the male epididymes (in mammals) for a period that can, in some cases, extend over several weeks or more, but here we use the term to refer only to sperm storage by females.
- diurnal
-
- active during the day, 2. lasting for one day.
- motile
-
having the capacity to move from one place to another.
- sedentary
-
remains in the same area
- acoustic
-
uses sound to communicate
- visual
-
uses sight to communicate
- carrion
-
flesh of dead animals.
- detritus
-
particles of organic material from dead and decomposing organisms. Detritus is the result of the activity of decomposers (organisms that decompose organic material).
- food
-
A substance that provides both nutrients and energy to a living thing.
- herbivore
-
An animal that eats mainly plants or parts of plants.
- folivore
-
an animal that mainly eats leaves.
- frugivore
-
an animal that mainly eats fruit
- omnivore
-
an animal that mainly eats all kinds of things, including plants and animals
References
Campbell, H., W. Evans. 1972. Observations on the Vocal Behavior of Chelonians. Herpetologica , 28/3: 277-280.
Campbell, H., W. Evans. 1967. Sound production in two species of tortoises. Herpetologica , 23/3: 204-209.
Ernst, C., R. Altenburg, R. Barbour. 1997. " Geochelone carbonaria " (On-line). Turtles of the World. Accessed May 26, 2011 at http://nlbif.eti.uva.nl/bis/turtles.php?selected=beschrijving&menuentry=soorten&id=380 .
IUCN, 1982. The IUCN Amphibia-Reptilia Red Data Book Part 1: Testudines, Crocodylia, Rhynchocaphalia . Gland, Switzerland: IUCN. Accessed June 15, 2011 at http://books.google.com/books?id=Nw8KKyu32v8C&pg=PA61&lpg=PA61&dq=Chelonoidis+carbonaria+IUCN&source=bl&ots=hBYuKrj0n8&sig=IDrMJWyAsL-dXO2VAoVJuRedu1I&hl=en&ei=hCD5TfqhCsrVgQeq46T7Cw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBoQ6AEwAA#v=onepage&q=Chelonoidis%20carbonaria&f=false .
Legler, J. 1963. Tortoises (Geochelone carbonaria) in Panama: distribution and variation. American Midland Naturalist , 70/2: 490-503.
Moskovits, D., A. Kiester. 1987. Activity levels and ranging behavior of the two Amazonian tortoises, Geochelone carbonaria and Geochelone denticulata, in north-western Brazil. Functional Ecology , 1/3: 203-214.
Moskovits, D., K. Bjorndal. 1990. Diet and food preferences of the tortoises Geochelone carbonaria and G. denticulata in northwestern Brazil. Herpetologica , 46/2: 207-218.
Spiess, P. 1997. "The Red-Footed Tortoise (Geochelone carbonaria) , a South American Treasure" (On-line). Accessed March 27, 2011 at http://www.kingsnake.com/rockymountain/RMHPages/RMHredfoot.htm .
Strong, J., J. Fragoso. 2006. Seed dispersal by Geochelone carbonaria and Geochelone denticulata in northwestern Brazil. Biotropica , 38/5: 683-686.
Wilkinson, A. 2010. Gaze following in the red-footed tortoise ( Geochelone carbonaria ). Animal Cognition , 13/5: 765-769.