The red-footed tortoise (''Chelonoidis carbonarius'')
is a species of
tortoise
Tortoises () are reptiles of the family Testudinidae of the order Testudines (Latin: ''tortoise''). Like other turtles, tortoises have a shell to protect from predation and other threats. The shell in tortoises is generally hard, and like oth ...
from northern
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sout ...
. These medium-sized tortoises generally average as adults, but can reach over . They have dark-colored, loaf-shaped
carapaces (back shell) with a lighter patch in the middle of each
scute
A scute or scutum (Latin: ''scutum''; plural: ''scuta'' "shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of birds. The term is also used to describe the anterior po ...
(scales on the shell), and dark limbs with brightly colored scales that range from pale yellow to dark red. Recognized differences are seen between red-footed tortoises from different regions. They are closely related to the
yellow-footed tortoise
The yellow-footed tortoise (''Chelonoidis denticulatus''), also known as the Brazilian giant tortoise, commonly referred to as the Brazilian giant turtle, or more commonly, the big turtle, is a species of tortoise in the family Testudinidae and ...
(''C. denticulatus'') from the
Amazon Basin. They are popularly kept as pets, and over-collection has caused them to be vulnerable to extinction.The species name has often been misspelled as ''carbonaria'', an error introduced in the 1980s when ''Chelonoidis'' was elevated to genus and mistakenly treated as feminine, an error recognized and fixed in 2017.
Their natural habitat ranges from
savannah to
forest edges around the Amazon Basin. They are
omnivorous
An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nut ...
with a diet based on a wide assortment of plants, mostly fruit when available, but also including grasses, flowers,
fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
,
carrion, and
invertebrates
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordat ...
. They do not
brumate, but may
aestivate in hot, dry weather.
Eggs, hatchlings, and juvenile tortoises are food for many predators, but the main threats for adults are
jaguars
The jaguar (''Panthera onca'') is a large cat species and the only living member of the genus ''Panthera'' native to the Americas. With a body length of up to and a weight of up to , it is the largest cat species in the Americas and the thi ...
and humans. Population density ranges from locally common to very scarce due in part to
habitat destruction
Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...
and over-collection for food and the pet trade.
Names
Red-footed tortoises have many common names: red-leg, red-legged, or red-foot tortoise (often without the hyphen) and the savanna tortoise, as well as local names, such as ''carumbe'' or ''karumbe'', which means 'slow moving' (Brazil,
Paraguay
Paraguay (; ), officially the Republic of Paraguay ( es, República del Paraguay, links=no; gn, Tavakuairetã Paraguái, links=si), is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to th ...
), ''wayapopi'' or ''morrocoy'' (
Venezuela
Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...
,
Colombia), and variations of ''jabuti'' such as ''japuta'' and ''jabuti-piranga'' (Brazil,
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
).
[ p. 27-29.] In Portuguese, ''
jabuti'' (''jaboti'') refers to both the red-footed tortoise and the
yellow-footed tortoise
The yellow-footed tortoise (''Chelonoidis denticulatus''), also known as the Brazilian giant tortoise, commonly referred to as the Brazilian giant turtle, or more commonly, the big turtle, is a species of tortoise in the family Testudinidae and ...
.
It is also called ''kati'' in
Natú[Pompeu Sobrinho, Thomaz. 1958. ''Línguas Tapuias desconhecidas do Nordeste: Alguns vocabulários inéditos''. Boletim de Antropologia (Fortaleza-Ceará) 2. 3-19.] and ''sambó'' in
Kiriri.
Taxonomy
Red footed tortoises were originally assigned to the
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
''
Testudo'' (named by
Carl Linnaeus
Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his Nobility#Ennoblement, ennoblement in 1761 as Carl von Linné#Blunt, Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalise ...
in 1758) for a short time, but it soon became the term for turtles with high-domed shells, elephantine legs, and completely terrestrial habits—the tortoises. In 1835,
Leopold Fitzinger used ''
Geochelone
''Geochelone'' is a genus of tortoises.
''Geochelone'' tortoises, which are also known as typical tortoises or terrestrial turtles, can be found in southern Asia. They primarily eat plants. Species
The genus consists of two extant species:
A ...
'' to differentiate some non-Mediterranean tortoises, apparently based on size and lack of specific identifying characteristics such as the hinged shell in the African
hingeback tortoises. He used the term ''Chelonoidis'' as a subgenus for the species from South America. Few people used these terms until they were resurrected by Hewitt in 1933 and Loveridge and Williams in 1957.
In 1982, Roger Bour and Charles Crumly each separated ''Geochelone'' into different genera based on anatomic differences, especially in the skulls. That resulted in the formation or restoration of several genera: ''
Aldabrachelys
''Aldabrachelys'' is the recognised genus for the Seychelles and Madagascan radiations of giant tortoises, including the Aldabra giant tortoise (''Aldabrachelys gigantea'').
Naming
This name is problematic in that the type specimen is actually r ...
'', ''
Astrochelys
''Astrochelys'' is a genus of tortoises in the family Testudinidae. The two species are both found in Madagascar, and both classified as critically endangered on the IUCN Red List
The International Union for Conservation of Nature (IUCN) R ...
'', ''
Cylindraspis'', ''
Indotestudo'', ''
Manouria
''Manouria'' is a genus of tortoises in the family Testudinidae. The genus was erected by John Edward Gray in 1854.
Species
The following five species are recognized as being valid, two of which are extant, and three of which are extinct:
*''Ma ...
'', and ''Chelonoidis''. ''Chelonoidis'' was distinguished from other ''Geochelone'' by their South American location, as well as the absence of the nuchal scute (the marginal centered over the neck) and the presence of a large, undivided supracaudal (the scute or scutes directly over the tail), as well as differences in the skull. Many of these generic names are still debated; for example, no specific definition of ''Geochelone'' is given, and ''Chelonoidis'' is primarily used for geography rather than unique anatomic characteristics.
[
, p. 204.]
The species name ''carbonarius'' means 'coal-like' referring to a dark coal with glowing patches. It was originally identified by
Johann Baptist von Spix in 1824. The
holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of sever ...
was kept in the
Zoologischen Sammlung des Bayerischen Staates in
Munich
Munich ( ; german: München ; bar, Minga ) is the capital and most populous city of the German state of Bavaria. With a population of 1,558,395 inhabitants as of 31 July 2020, it is the third-largest city in Germany, after Berlin and Ha ...
, Germany, but was lost.
Paulo Vanzolini
Paulo Emilio Vanzolini (; April 25, 1924 – April 28, 2013) was a Brazilian scientist and music composer. He was best known for his samba compositions, including the famous ''"Ronda", "Volta por Cima"'', and ''"Boca da Noite"'', and for his sci ...
believes it may have come from near the city of
Manaus, Brazil, on the
Rio Negro. No subspecies of red-footed tortoise are recognized, although many believe the species has five or more variants that may be subspecies or even separate species.
Description
Red-footed tortoises show sex, regional, and individual variations in color, shell shape, and minor anatomical characteristics. Adult 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 (although the scutes may be raised or 'pyramided' in some individuals, especially captive specimens). Often, a high point over the hips is seen, with 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 botany, areoles are small light- to dark-colored bumps on cacti out of which grow clusters of spines. Areoles are important diagnostic features of cacti, and identify them as a family distinct from other succulent plants. Gordon Rowley - W ...
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 brown, almost black
iris
Iris most often refers to:
*Iris (anatomy), part of the eye
*Iris (mythology), a Greek goddess
* ''Iris'' (plant), a genus of flowering plants
* Iris (color), an ambiguous color term
Iris or IRIS may also refer to:
Arts and media
Fictional ent ...
, and rarely any
sclera visible around it. The upper jaw is slightly hooked, and the upper jaw is notched in the front middle. About 15 to 20 'teeth' or fine grooves occur 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 five claws on the fore limbs and four on the hind, but no visible toes. The fore limbs 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
The African spurred tortoise (''Centrochelys sulcata''), also called the sulcata tortoise, is a species of tortoise inhabiting the southern edge of the Sahara desert in Africa. It is the largest mainland species of tortoise in the world, and the ...
(''Geochelone sulcata''). The tail is muscular, varies in length and overall shape by sex, and lacks any sort of claw on the tip.
Average adult sizes vary by region and sex, and 'giants' are often encountered. Red-footed tortoises average with males slightly larger overall. Tortoises up to are fairly common and over are occasionally discovered. The largest known specimen, from Paraguay, was long, and weighed over . 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 of each scute. The marginals of very young tortoises 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.
Males are slightly larger and more colorful overall. The carapace of a male from north of the Amazon basin shows a 'wasp waist', or constrictions along the sides. The male's plastron is deeply indented to help with positioning during mating. The male's tail is long and muscular, generally carried along a side while the female's tail is short and conical.
The anal scutes vary to allow the male's tail more mobility and allows more protection for the female's hind end. The gap between the points of the anal scales and the marginals is wider and the anal scutes form a broader angle- almost a straight line across- in males to allow the tail to move laterally. The angle is more closed (to about a 90° angle) and the points are closer to the marginals in females.
Distribution and habitat
Red-footed tortoises range from southeastern Panama to Venezuela,
Guyana,
Suriname, and
Guiana in the north; south along the
Andes
The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...
to the west in Colombia,
Ecuador
Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ' ...
,
Peru
, image_flag = Flag of Peru.svg
, image_coat = Escudo nacional del Perú.svg
, other_symbol = Great Seal of the State
, other_symbol_type = National seal
, national_motto = "Firm and Happy f ...
, and
Bolivia; east to Brazil, and along the southern range in Bolivia, Paraguay, and possibly northern
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...
. They are not evenly distributed within their range. For example, they are not often found in central Brazil or in heavily forested areas in general, and have only documented in Peru since 1985. Accurate range information is complicated by the sheer size of the range, political and geographic barriers, and confusion about where many specimens were collected.
They are also found on several
Caribbean Islands, although it is not always clear if they are native or brought by humans. Many of the colonies seem to have been established in the 17th century as food supplies or as pets. They are found on the former
Netherlands Antilles, Trinidad, Tobago, Grenada, Barbados, St. Vincent, the Grenadines, Santa Lucia, Martinique, Dominica, Guadalupe, the Leeward Islands, the Virgin Islands, and Puerto Rico.
The preferred habitat of the red-footed tortoise varies somewhat by region, but generally includes fairly consistent seasonal temperatures near that rarely get lower than or over , generally with high humidity and plenty of rainfall, although some of the areas can get quite dry. Most of the range experiences cooler wet seasons (April to August) and warmer dry seasons (September to March), but some parts of the southern range have occasional cold snaps. Red-footed tortoises are often found in or near transitional areas between forest and savannah, such as forest clearings, wood edges, or along waterways.
Regional variations
Various authors have divided the red-footed tortoise into different groups by anatomy and geography.
Peter Pritchard
Peter Charles Howard Pritchard (June 26, 1943 – February 25, 2020) was a leading turtle zoologist. Pritchard was educated at Oxford University and the University of Florida, where he received a Ph.D. and specialized in Zoology. He was most com ...
recognized seven types,
but DNA research has identified five genotypes.
The most obvious differences are between the groups found north or south of the Amazon basin. The 'northern' variants all look very much like the holotype and are distinguished primarily by shell, head, and limb coloration. The variants south of the Amazon are generally both larger and smaller than the holotype, have a very different plastral pattern, and have an enlarged scale or 'spur' on the inside of the fore limb elbow.
Northeastern variant
This is the holotype of the species. Head and limb colors are generally light orange to red. Plastrons are mostly pale yellow. They range in the
Guiana Shield
The Guiana Shield (french: Plateau des Guyanes, Bouclier guyanais; nl, Hoogland van Guyana, Guianaschild; pt, Planalto das Guianas, Escudo das Guianas; es, Escudo guayanés) is one of the three cratons of the South American Plate. It is a ...
- Venezuela, Guyana, Suriname, Guiana, and northern Brazil.
Northwestern variant
They are similar to the northeastern variant, but their carapace base color is grey, dark brown, or coffee rather than black. Their pale plastrons have central dark areas resembling an exclamation point. Their heads and limbs are generally pale yellow to orange. The average size is slightly smaller than usual- 30–35 cm. They are found in southeast Panama and Colombia.
Northern variant
These also are similar to the northeastern variant, with head and limb colors generally pale yellow to light orange, rarely red, and their heads and limbs are often slightly different colors. The average size is slightly smaller than usual- 30–35 cm. They are found in Colombia, Ecuador, and Peru.
[ pp. 7-10.]
Southern variant
The southern variants' carapaces are often not quite black to dark brown, sometimes with light grey or whitish between the scutes. Their plastrons are mostly dark in a symmetrical mottled pattern. Size tends to be larger on average then northeastern variants, with the largest individuals found in this area. Fore limbs feature a slightly enlarged scale on the side of the 'elbow'. Adult males do not have the constricted waist, and females average a bit larger than the males. They are seen in the
Gran Chaco
The Gran Chaco or Dry Chaco is a sparsely populated, hot and semiarid lowland natural region of the Río de la Plata basin, divided among eastern Bolivia, western Paraguay, northern Argentina, and a portion of the Brazilian states of Mato ...
- Bolivia, Paraguay, and northern Argentina.
Eastern variant
Carapaces of the eastern variants are often light grey or whitish between the scutes. Their plastrons are mostly dark in a symmetrical mottled pattern. Size tends to be smaller on average than northeastern variants, also reaching sexual maturity at a smaller size. Fore limbs feature a slightly enlarged scale on the side of the 'elbow'. Their heads and limbs are either yellowish or red, ranging to brilliant cherry-red. They are located in east to southeast Brazil. The red-headed type of this variant is often called a 'cherry-head' in the pet trade.
Population features
Little information is available about population density or sex ratios. Many specimens are recorded from near research stations and cities, but that is almost certainly more due to the ease of finding them there than higher localized populations. They are considered one of the most common turtle species in many localities. When a dam was being built in the Edo region of Venezuela, several hundreds of the red- and yellow-footed tortoises were captured for relocation. Large numbers are also found in markets, confiscated at airports, etc.
However, very few records exist from Peru, Ecuador, Argentina, and central Brazil. In the Guiana Shield region, islands of higher populations and stretches where few have been located are seen.
Counting tortoises that are often well-hidden, dug in, deep in burrows, etc. is difficult. Trained dogs discover many that otherwise might not be found. One study showed a nearly balanced mix of 1.32 males per female, and 1.05 red-footed tortoises per
hectare
The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100- metre sides (1 hm2), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is ...
(2.4 acres) on the island, which may be an underestimate due to the difficulty in finding the tortoises.
[
p. 41-42]
Evolutionary history and fossil record
The genus ''Chelonoidis'' has two main subcategories based on appearance and habitat- the ''C. carbonarius'' and the ''C. chilensis'' groups. The ''C. carbonarius'' group has the closely related red- and yellow-footed tortoises that clearly share a common ancestor. The ''C. chilensis'' group features the
Chaco tortoise (''C. chilensis'') and
Galápagos tortoise
The Galápagos tortoise or Galápagos giant tortoise (''Chelonoidis niger'') is a species of very large tortoise in the genus ''Chelonoidis'' (which also contains three smaller species from mainland South America). It comprises 15 subspecies ( ...
(''C. niger''), which share similar habitats and a basic appearance, but otherwise do not seem to be closely related. The relationship between the groups is unclear.
Several theories are offered to explain the relatively small number of tortoise species in South America and the relationship between them, but the fossil record is not very complete. One long-held theory is that they came from Asia using the land bridge, then spread down through North America and shared ancestors with the gopher tortoises (''
Gopherus'' species). Another holds ''Geochelone'' ancestors floated over from central Africa, taking advantage of their ability to float, resist salt water, and go without food for extended periods.
DNA studies suggest that the ''carbonarius'' group may be related to the African
hingeback tortoises (''Kinixys'' species).
This suggests that they might have come from
Gondwana before it separated into Africa and South America some 130 million years ago. One ancestral form from about 5mya, ''Chelonoidis hesterna'' (Auffenberg 1971), is thought to have lived in wet forests and split into two species in the
Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
with the yellow-footed tortoises remaining in the deep forest and the red-footeds colonizing the edges of the forests and the emerging savannahs. As the climate and topography changed, groups of red-footed tortoises became physically separated and genetically isolated.
Ecology and behavior
The red-footed tortoise's climate in the northern part of the range changes little day to day and rarely gets too hot for them, so the tortoises do not need to practice any form of
dormancy and can often forage all day long. The tortoises in Moskovitz's study area were most active after 3:00pm while many species from warmer climes would be most active in the morning and evening. Tortoises from the southern parts of the range experience much hotter, colder, and drier conditions than most of the range and aestivate when food becomes scarce. They may aestivate or brumate when the temperatures are low enough.
Most species of tortoise spend much of their day inactive, and red-footed tortoises generally spend over 50% of the daylight hours at rest. They may rest for even longer after a large meal, with five- to ten-day stretches being common. One large specimen seems to have stayed in the same position for over a month. Resting tortoises barely move, allowing leaf litter to accumulate on them, and
termites
Termites are small insects that live in colonies and have distinct castes (eusocial) and feed on wood or other dead plant matter. Termites comprise the infraorder Isoptera, or alternatively the epifamily Termitoidae, within the order Blattod ...
have built tunnels on the carapaces of resting red-footed tortoises.
They seek shelter in places that offer
thermoregulation
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...
and protection from predators. Treefalls are a favored site, as are debris piles, burrows (especially those of the
armadillo (''Dasypodidae'' family) and
agouti
The agouti (, ) or common agouti is any of several rodent species of the genus ''Dasyprocta''. They are native to Middle America, northern and central South America, and the southern Lesser Antilles. Some species have also been introduced else ...
(''Dasyprocta'' species)), hollow logs, holes, and heavy vegetation cover. They generally try to find tight-fitting resting places, and will occasionally 'wedge' themselves between roots and trunks but remain otherwise exposed. Burrows and holes are often flooded and the tortoises will rest in the water and mud with just their nostrils and eyes exposed. In warmer weather, they press up against moister, cooler surfaces in shelter areas. The tortoises show personal preferences with many individuals always seeking out a specific type of shelter.
Shelters are often communal with as many tortoises as can fit in the space. Good shelters are so important, and visibility is so poor that the tortoises will leave scent trails that they or others can follow.
Some shelters are so heavily used by tortoises that clear trails in the dirt lead to them, though individual tortoises may not return to a given shelter regularly.
[
]
Besides communal shelters and scent marking, red-footed tortoises also show other signs of semisocial behavior such as lack of aggression at feeding sites, not protecting territory, and group feeding at fruit falls and carrion (although it is not unusual for one tortoise to block access or even try to make off with some of the food). Red-footed tortoises often follow each other, usually a smaller one following a larger and quite often males following males, but all combinations are seen. They have also been observed following apparent scent trails laid by an individual a day or two earlier.
Predators
Hatchling and young tortoises are at high risk of predation. Tegu lizards (''
Tupinambis
''Tupinambis'' is a lizard genus which belongs to the family Teiidae and contains eight described species. These large lizards are commonly referred to as tegus (''teiús'' in Portuguese). '' T. merianae'' (Argentine black and white tegu), '' T ...
'' species), ring-tailed
coatis
Coatis, also known as coatimundis (), are members of the family Procyonidae in the genera '' Nasua'' and '' Nasuella''. They are diurnal mammals native to South America, Central America, Mexico, and the southwestern United States. The name ...
(''Nasua nasua''), and introduced rats and mongooses attack nests and eggs. Many predators take the young tortoises, including large lizards, snakes, crocodilians, and even large turtles; predatory birds such as the curassow (''
Crax'' species), guan (''
Penelope
Penelope ( ; Ancient Greek: Πηνελόπεια, ''Pēnelópeia'', or el, Πηνελόπη, ''Pēnelópē'') is a character in Homer's ''Odyssey.'' She was the queen of Ithaca and was the daughter of Spartan king Icarius and naiad Periboea. Pe ...
'' species),
rails
Rail or rails may refer to:
Rail transport
*Rail transport and related matters
*Rail (rail transport) or railway lines, the running surface of a railway
Arts and media Film
* ''Rails'' (film), a 1929 Italian film by Mario Camerini
* ''Rail'' ( ...
,
cuckoo
Cuckoos are birds in the Cuculidae family, the sole taxon in the order Cuculiformes . The cuckoo family includes the common or European cuckoo, roadrunners, koels, malkohas, couas, coucals and anis. The coucals and anis are sometimes separ ...
s, and
falcon
Falcons () are birds of prey in the genus ''Falco'', which includes about 40 species. Falcons are widely distributed on all continents of the world except Antarctica, though closely related raptors did occur there in the Eocene.
Adult falcons ...
s; and mammals such as cats (
Felidae species),
opossums,
foxes,
peccaries
A peccary (also javelina or skunk pig) is a medium-sized, pig-like hoofed mammal of the family Tayassuidae (New World pigs). They are found throughout Central and South America, Trinidad in the Caribbean, and in the southwestern area of North ...
, and feral dogs.
Other than humans, the main predators of the adult tortoises are
jaguars
The jaguar (''Panthera onca'') is a large cat species and the only living member of the genus ''Panthera'' native to the Americas. With a body length of up to and a weight of up to , it is the largest cat species in the Americas and the thi ...
(''Panthera onca''). Red-footed and yellow-footed tortoises seem to be a significant food source for jaguars in some parts of their respective ranges, such as
Manú National Park
Manú National Park ( es, Parque Nacional del Manú) is a national park and biosphere reserve located in the regions of Madre de Dios and Cusco in Peru. It protects a diverse number of ecosystems including lowland rainforests, cloud forests and ...
in Peru. Jaguars bite at the carapace and work at cracking or prying it apart to extract the soft tissues. Many tortoises show toothmarks from attacks that they survived, often on the hind end when they were otherwise protected in a burrow or shelter.
Diet
Discussing the diet of the red-footed tortoise is difficult due to the wide variety of foods it eats, the variety and seasonal availability of plants available across the extensive range, interpreting what field reports are trying to describe,
[
] and because studying fecal pellets gives very different results than what the animals are observed eating.
Forest-dwelling tortoises in the ''Chelonoidis'', ''Indotestudo'', ''Manouria'', and ''Kinixys'' genera are omnivores with upper and lower intestines about the same length, while herbivorous genera such as ''Gopherus'' and ''Testudo'' have longer large intestines to digest fibrous grasses. Most omnivorous tortoises have no other specialized digestive structures, reflecting their generalized, flexible diet.
The bulk of the diet is some sort of fruit or seed pod. Common fruits come from cacti (''
Opuntia''), figs (''
Ficus
''Ficus'' ( or ) is a genus of about 850 species of woody trees, shrubs, vines, epiphytes and hemiepiphytes in the family Moraceae. Collectively known as fig trees or figs, they are native throughout the tropics with a few species extendi ...
''), pehen (''
Acacia aroma''), ''
Spondias
''Spondias'' is a genus of flowering plants in the cashew family, Anacardiaceae. The genus consists of 17 described species, 7 of which are native to the Neotropics and about 10 are native to tropical Asia. They are commonly named hog plums, Sp ...
'', ''
Annona'', ''
Philodendron
''Philodendron'' is a large genus of flowering plants in the family Araceae. , the World Checklist of Selected Plant Families accepted 489 species; other sources accept different numbers. Regardless of number of species, the genus is the second- ...
'',
bromeliads, and more. Up to five different kinds of fruits are often found in fecal pellets.
The entire fruit is eaten, and the seeds are passed and can germinate, giving red- and yellow-footed tortoises a significant role in seed dispersal. Red-footed tortoises have been observed at the base of fruit trees, apparently waiting for fruit to fall.
The rest of the diet includes grasses, leaves, flowers, roots, and shoots from a wide assortment of plants as well as
fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
, live
invertebrates
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordat ...
(such as ants, termites, beetles, butterflies, snails, and worms), carrion, and feces (especially from foxes). Tortoises are often found at carcasses feeding until gorged, and occasionally eat small live animals such as snakes and rodents. Pebbles and sand are also often found in fecal pellets.
The diet changes based on season and availability. In the wet season it may be roughly 70% fruit, 25% fresh leaves and shoots, and the rest being fungi and animal food. The dry season sees 40% fruits, 23% flowers, 16% fresh leaves and shoots, and the rest fungi, moss, and animal food.
Omnivorous tortoises seek out foods high in calcium even if other foods are more readily available, and even eat mineral-rich soil if they cannot get adequate calcium in the diet.
Movement
Red-foot tortoises forage over areas ranging from usually making a 'spiderweb' pattern centered on a good hide or a recent fruit fall. They generally move methodically around 5 to 20 m/hr (5.5-22 yd/hr), but can raise up on their long legs and move up to 100 m/hr (109 yd/hr) when they want. While they generally forage in zig-zag or looping patterns, they sometimes move or more in fairly straight lines, often at a rapid pace. They show a marked preference for moving under medium to dense vegetation cover.
Lifecycle
All turtles and tortoises start as eggs. Red-footed tortoise eggs are roughly spherical and average around and weigh with two to seven eggs in a clutch, although the same females may lay multiple clutches near each other. The incubation period is 105–202 days, with 150 being typical.
Hatchlings use an egg tooth to open the egg. They stay in the egg or nest for several days. Hatchling shells are bent almost in half in the egg and take some time to straighten out. The hatchling's carapace is flat, somewhat creased from being folded in the egg, and has serrated sides. Little is known of the daily activities or diet of hatchling wild tortoises.
Subadult tortoises grow quickly to reach breeding sizes- roughly , depending on the average adult size of the regional variant.
[
]
The peak time for courtship and reproduction is the early wet season in April and May, although it can happen at any time. Courtship noises and possibly scent cues seem to attract other tortoises to 'courting sites' under fruiting trees such as ''
Genipa
''Genipa'' is a genus of trees in the family Rubiaceae. This genus is native to the American tropical forests.
Description
Tall trees, without any spines, prickles or thorns; with large opposite leaves of almost leathery texture, smooth or ha ...
''.
When two tortoises meet about a meter apart, they engage in some specific behaviors to identify the other. The first trigger is head and limb color; the bright red, orange, yellow, or white colors on the dark skin identify the other animal as the proper species. Next, the larger tortoise makes jerky side-to-side head movements for two to four seconds. If both tortoises are males, one will either withdraw and retreat, or they may try to ram each other, trying to get their gular scutes under the other one, then pushing them several meters away as quickly as possible. The defeated tortoise is sometimes flipped onto his back in the process. The defeated tortoise will leave the area afterwards. Neither head bobbing nor ritual combat have been observed in tortoises south of the Amazon Basin, possibly due to the lack of yellow-footed tortoises in the area. Males mounting other males, and even females mounting either sex have been witnessed and are thought to show dominance.
If the other tortoise is a female, she will move away and the male will follow, touching her carapace and occasionally sniffing at her cloaca. If the female stops, the male may either wait for her to resume moving or leave. Males make loud 'clucking' sounds during the chase. After trailing, the male mounts the female, his feet planted on the costals of her carapace, rams his anal scutes against her supracaudal, and makes a loud raspy 'bark'. If the female resumes walking, he may fall off and resume trailing. Females sometimes seem to intentionally use low limbs to knock males off. A receptive female extends her hind legs and lifts her plastron as the male plants himself on his own extended hind legs as he works to align their cloacae for insertion. The tail, scutes, an
penisof the tortoise are designed to work around the awkwardness of the shell. The male often leans his head over her head and holds his jaws wide open making calls that get louder. He may bite her, as well, sometimes quite aggressively. The shells can make loud clacking noises during the forceful thrusts. The female walks away after copulation, sometimes knocking the male off her.
The female begins nesting five to six weeks after mating. Digging the nests is often difficult in hard soil. The female may urinate to soften the soil before using her hind legs to dig a chamber about in about three and a half hours. Inexperienced females often dig several partial nests, and even experienced females may abandon a nest they are working on and start another. When the nest is ready, she lowers her tail as deep into the nest as she can and deposits an egg every 30 to 120 seconds. She recovers the nest and tamps the soil down. Females get better at digging, covering, and camouflaging nests over time. After it is covered and hidden, she often gets a long drink of water, then finds a shelter and rest. Very rarely, a red-footed tortoise lays eggs on the surface, or within a patch of cacti.
As with other tortoises, red-footed tortoises can reproduce most of their lives, although the number of eggs laid and the ratio of successful hatchlings improves as the tortoise matures, then drops off again as the tortoise ages. Because of the difficulty in determining the age of a wild tortoise, few data on longevity exist, although many live for 30 years or more in captivity.
Conservation and relations with humans
The red-foot tortoise is considered vulnerable and is listed in
CITES
CITES (shorter name for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of interna ...
Appendix II, restricting international trade- although this does not offer protection within a country and smuggling still occurs in large numbers. Conservation parks and refuges, captive-breeding farms in natural conditions, and increased captive breeding in other countries has helped, but they are still exported in large numbers (35,565 from 2000 to 2005), mostly as pets and food.
The recorded exports do not include smuggling or other losses, which some estimate to be well over twice that number. They are considered especially at risk in Argentina and Colombia, and are considered more at risk than yellow-footed and
Chaco tortoises.
They are widely used as food throughout their ranges, especially where other meats are limited. Their ability to go a long time without eating makes it easy to catch and keeps them fresh for extended periods. The
Catholic Church
The Catholic Church, also known as the Roman Catholic Church, is the largest Christian church, with 1.3 billion baptized Catholics worldwide . It is among the world's oldest and largest international institutions, and has played a ...
allows tortoises to be eaten on fasting days when most meats are forbidden such as
Lent
Lent ( la, Quadragesima, 'Fortieth') is a solemn religious observance in the liturgical calendar commemorating the 40 days Jesus spent fasting in the desert and enduring temptation by Satan, according to the Gospels of Matthew, Mark and Luke ...
. Tortoise pie (''pastel de morrocoy'', served in a tortoise shell) is a favorite food for those times, and large numbers of tortoises are exported just for that purpose. Even people living in countries with an abundance of available livestock enjoy wild game, such as tortoises, when possible. Hunting for food is so extensive that Colombia and some other countries import tortoises from neighbors.
Habitat destruction
Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...
is another significant threat to the red-footed tortoise, and so many other species. They are also widely collected as local pets and their shells are sold as souvenirs.
Captive care
Red-footed tortoises are popular pet tortoises around the world. They are relatively inexpensive, are a manageable size, have interesting personalities, and are colorful.
Pet tortoises should be purchased as captive-bred from a reliable breeder when possible to both help protect wild populations and to avoid internal parasites.
Any reptile can carry ''
Salmonella'' species, so keepers should practice proper hygiene, such as washing their hands after handling the animals or their wastes. Dogs, even well-behaved dogs, often attack or chew on tortoises, so great care must be taken if they are around.
Housing
All tortoises should be housed outdoors when conditions allow. Outdoor pens should allow space for exercise, secure walls that are at least 1.5 times taller than the tortoise is long, and security from both predators and escape. Shelter and water should always be provided.
Indoor housing is generally scaled to the size of the tortoise and must be secure and waterproof for this high-humidity species, as well as offering adequate space. Aquaria and plastic tubs are often used for younger tortoises, while a "tortoise table" (similar to shelf-less bookcase lying on its back), indoor minigreenhouse, or large indoor pen can be used for larger tortoises or groups of tortoises.
An indoor habitat should be lined with a substrate such as hardwood mulches (like cypress), coconut coir, soil and sand mixes, or some combination. A hide and water dish are necessary, and live or silk plants also help.
Environment
Heat, light, and humidity must be kept within proper guidelines for healthy tortoises. Red-footed tortoises are most active at temperatures from . A warmer area of is recommended, and night temperatures can drop a few degrees lower. High levels of humidity should be available in some part of the habitat.
Lighting should be low and diffuse or plenty of shade should be offered. Lights that emit
UVB
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...
wavelengths are recommended to help the tortoise metabolize calcium correctly and help regulate the
pineal gland if the tortoise will be indoors for extended periods.
Captive diet
Pet tortoises should be allowed to forage in a well-planted outdoor pen whenever possible. The basic diet should consist of a variety of plants, vegetables, and fruits with occasional meat, and be high in calcium and fiber, and low in sugars and fats. Fruits should be kept as whole as possible. Commercial tortoise pellets can be offered along with fresh foods.
The bulk of the diet should be leafy greens such as turnip or collard greens, dandelion, leafy or curly lettuces, endive, kale, cabbage, edible tree or plant leaves such as mulberry or hibiscus, lettuce mixes, parsley, grape leaves, etc.
Vegetables and fruits offer variety and other nutrients, but are a smaller part of the captive diet. Good choices would include: cactus pads and fruits, papaya, figs, mango, mushrooms, pumpkin, squash, melon, pineapple, strawberry, cucumber, hays and grasses (such as wheatgrass), corn, peas and beans, carrot, apple, pear, plums, and okra.
Meats form a very small part of the captive diet, and can include live bugs or invertebrates (especially slugs), baby mice or rats, chicken, egg, organ meat, lean beef, tuna or other 'oily' fish, or cat or dog food.
Calcium should be supplemented frequently in very small amounts. Other vitamins can be offered in very small amounts as well, but are best provided through a balanced, varied diet.
[Pingleton, p. 77-80.]
References
External links
See video of red-footed tortoises at the Naples ZooRed Foot Tortoisegov.vi
{{DEFAULTSORT:Red-Footed Tortoise
Chelonoidis
Turtles of South America
Reptiles of the Caribbean
Reptiles of Saint Barthélemy
Reptiles of Saint Martin (island)
Reptiles of Guyana
Vulnerable animals
Vulnerable biota of South America
Reptiles described in 1824
Articles containing video clips