Geochelone elegansStar Tortoise

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Geographic Range

Geochelone elegans is found in three discrete portions of the Indian subcontinent: the first is in western India and extreme southeastern Pakistan (e.g., Gujarat, Rajasthan, and Uttar Pradesh in India and the Thar Desert in Pakistan), the second is in southeastern India (Karnataka, Kerala, Tamil Nadu), the third is on the island of Sri Lanka. No subspecies are recognized, although there are regional variations in color and morphology. In general, star tortoises from northern India tend to be larger and darker, with less contrasting shell patterns, than those from southern India, which tend to be smaller and have more contrasting, star-like shell patterns. Sri Lankan tortoises may have more contrasting shell patterns with broader yellow markings and they tend to reach larger sizes than southern Indian tortoises. However, much variation occurs among individual star tortoises and within local populations. ("Honolulu Zoo", 2008; "Manhattan, Kansas", 2001; Das, 1995; Das, 2002; Ernst and Barbour, 1989; Fife, 2007; Tabaka and Senneke, 2006)

Habitat

Indian star tortoises occupy a wide range of habitats, including moist deciduous forest, semi-arid lowland forests, thorn scrub forests, arid grasslands, and semi-desert. These tortoises have a high tolerance for seasonally wet or dry habitats, with many populations living in areas with a monsoon (rainy) season followed by an extensive hot and dry period. They sometimes live in agricultural areas. ("Manhattan, Kansas", 2001; Das, 1995; Fife, 2007; Subramanyam, et al., 2006)

  • Range elevation
    0 to 450 m
    0.00 to 1476.38 ft

Physical Description

Indian star tortoises have yellow to tan heads, limbs, and tails, though the skin may be marked with dark spots or blotches. The carapace is the most striking feature of this tortoise and can have smooth to almost pyramidal scutes. Each scute has a yellowish areola (center) with yellow or tan lines radiating from it, forming the star shape for which this species is named. The marginal scutes have incomplete “stars”. Background color is brown to black. The plastron has dark radiating lines on a lighter yellowish background. ("Honolulu Zoo", 2008; Das, 1995; Ernst and Barbour, 1989; Fife, 2007; Rajaratnam, 2008; Subramanyam, et al., 2006)

Females are often markedly larger than males. An adult male’s carapace typically grows to a straight-line length of 15 to 20 cm (about 6 to 8 inches), and females reach 25 to 30 cm (about 10 to 12 inches). The record reported carapace length (female) is 38 cm (about 15 inches). ("Manhattan, Kansas", 2001; Das, 1995; Ernst and Barbour, 1989; Fife, 2007)

Besides adult size differences, the sexes may be separated by morphological characters. Adult males have longer, thicker tails, and a concave plastron (which facilitates mounting and mating). Males have a different form of the paired anal scutes (posterior scutes of the plastron)— these scutes are more elongate and have a wider angle of separation than in the female. Conversely, females have shorter tails and flat plastrons. The anal scutes of females are shorter, with a narrower angle of separation directed more towards the rear of the plastron. (Das, 1995; Ernst and Barbour, 1989; Fife, 2007)

  • Sexual Dimorphism
  • female larger
  • sexes shaped differently
  • Range mass
    1 to 6.6 kg
    2.20 to 14.54 lb
  • Range length
    15 to 38 cm
    5.91 to 14.96 in

Development

Indian star tortoises are oviparous; their eggs have a hard but brittle shell that is quite porous. The eggs are usually elliptical in shape, but sometimes nearly spherical. They weigh between 12 and 21 grams, and are typically about 35 to 52 mm (1.4 to 2.1 inches) in length. Larger females can lay larger eggs. At first the eggs are translucent and pinkish in color, but tend to "chalk" (become opaque white) after two to three weeks, starting from a central belt of opacity and progressing to eventually envelope the whole shell. Sex determination is temperature dependent, with mostly males reportedly produced at incubation temperatures between 28 and 30 degrees Celsius and mostly females resulting from incubation temperatures from 31 to 32 degrees Celsius. Incubation times are probably temperature (and perhaps humidity) dependent; most eggs hatch in around 90 to 170 days (known range, 47 to 180 days). Hatchlings lack the radiating star markings; the carapace is usually black or brown with rectangular yellow or orange blotches on each scute that extend outward at the corners. They can grow rapidly for the first few months of their lives. ("Manhattan, Kansas", 2001; Das, 1995; Das, 2002; Edqvist, 2008; Ernst and Barbour, 1989; Fife, 2007; Subramanyam, et al., 2006; Tabaka and Senneke, 2006)

  • Development - Life Cycle
  • temperature sex determination

Reproduction

Males compete for mates by trying shove rival males or flip them onto their backs. Courtship is somewhat more subdued than in many other species of tortoises, often with little or no shoving, butting, and biting of females - which are often much larger than the males in this species. During mating, the male emits grunt-like sounds. (Das, 2002; Edqvist, 2008; Ernst and Barbour, 1989; Fife, 2007; Subramanyam, et al., 2006)

When the rainy season arrives (mid June to November in south India), breeding commences. About 60 to 90 days post-mating, usually in the evening, females begin wandering and sniffing the ground. When a female finds an acceptable nest site, she often urinates to soften the soil and begins excavating a flask-shaped nest with her hind feet. After she has laid her eggs, she re-fills the nest and flattens the soil with her plastron. The female lays from one to as many as nine clutches, of one to ten eggs per clutch, each year. Incubation lasts from 47 to 180 days; hatchlings weigh between 25 and 45 g and average about 35 mm in carapace length. In the wild, females may become sexually mature in 8 to 12 years and males in 6 to 8 years, but these times can be shortened considerably in captive tortoises. ("Manhattan, Kansas", 2001; Das, 1995; Edqvist, 2008; Ernst and Barbour, 1989; Fife, 2007; Subramanyam, et al., 2006)

  • Breeding interval
    Indian star tortoises breed during the rainy seasons, laying up to 9 clutches during that time.
  • Breeding season
    Indian star tortoises breed seasonally, usually coinciding with the local rainy season, which varies in timing.
  • Range number of offspring
    1 to 10
  • Range gestation period
    47 to 180 days
  • Range time to independence
    0 (low) minutes
  • Range age at sexual or reproductive maturity (female)
    7 to 12 years
  • Range age at sexual or reproductive maturity (male)
    6 to 8 years

Males expend considerable energy seeking females and fending off rival males. Females must contribute considerable energy towards producing and provisioning (yolking) eggs and constructing nests. There is no post-nesting parental care of eggs or hatchlings. (Das, 2002; Fife, 2007)

  • Parental Investment
  • no parental involvement
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female

Lifespan/Longevity

No studies on natural survivorship or lifespan in nature are available. As with other chelonians, presumably the eggs and small hatchlings and juveniles suffer the highest levels of mortality, with increasing survivorship as tortoises reach adulthood. Thus average lifespan might be considerably lower than potential lifespan. (Klemens, 2000; Slavens and Slavens, 1999; Subramanyam, et al., 2006)

  • Range lifespan
    Status: captivity
    25 (high) years
  • Typical lifespan
    Status: wild
    35 to 80 years

Behavior

During dry, hot weather Indian star tortoises are mostly active during the early morning and late afternoon. The rest of the day, these tortoises shelter under vegetation or other cover. During the rainy season, their activity level increases tremendously and they can be observed moving around and feeding during much of the day. In western India and Pakistan they become inactive during the colder winter months. (Das, 1995; Fife, 2007; Subramanyam, et al., 2006)

Home Range

There is no information available on home range size in Indian star tortoises. (Das, 1995)

Communication and Perception

Communication and perception appears to be primarily visual, though olfactory and tactile senses come into play during feeding, male competitive behavior, courtship, and nesting, and male tortoises vocalize to females during mating. (Das, 1995; Ernst and Barbour, 1989; Fife, 2007)

Food Habits

Indian star tortoises are primarily herbivorous. The majority of the diet consists of grasses, herbaceous leaves, fruit, and flowers, but they have been known to consume insects, carrion, and dung. When food is scarce, such as in the seasonally dry, hot periods, they will become inactive and go long periods without eating. ("Honolulu Zoo", 2008; Das, 1995; Ernst and Barbour, 1989; Fife, 2007; Subramanyam, et al., 2006)

  • Plant Foods
  • leaves
  • fruit
  • flowers
  • Other Foods
  • dung

Predation

As adults Indian star tortoises are protected by their heavy shells and habit of staying under cover when not actively foraging or breeding. While the star-like pattern on the carapace looks conspicuous when a tortoise is held in hand, the pattern actually breaks up and obscures the shape of the tortoise when it is hiding in tall grasses. Reports on natural predation on Indian star tortoises are scarce, but this species undoubtedly suffers heavy losses of eggs and young tortoises from a variety of predatory mammals (jackals, foxes, mongoose, etc.), birds (hawks, vultures, etc.), and large reptiles (monitor lizards, snakes). Humans are the most significant predator of juvenile and adult Geochelone elegans; these tortoises have been traditionally collected for local consumption and in recent decades have been systematically collected in large numbers for the commercial food and pet trade. ("Manhattan, Kansas", 2001; Das, 1995; Das, 2002; Fife, 2007; Gaur, et al., 2006; Rajaratnam, 2008; Subramanyam, et al., 2006)

  • Anti-predator Adaptations
  • cryptic

Ecosystem Roles

While species-specific studies are scarce, Indian star tortoises are undoubtedly significant herbivores in their habitats when abundant and they may act as dispersal agents for various plants via consumption (and incomplete digestion) of seeds and fruit. Star tortoises are hosts to numerous external and internal parasites, such as ticks and intestinal worms. (Das, 1995; Ernst and Barbour, 1989; Fife, 2007)

  • Ecosystem Impact
  • disperses seeds
Commensal/Parasitic Species

Economic Importance for Humans: Positive

Indian star tortoises have undoubtedly been used for human food ever since the two species came into contact thousands of years ago. Local subsistence use might not have seriously impacted tortoise populations, but systematic mass collection for the commercial food and pet market is unsustainable, reducing or even extirpating tortoise populations. The impact is made more significant when coupled with massive on-going habitat losses occurring in recent years. Indian star tortoises are popular in the pet trade because of their beautiful markings and relatively small size. Indian star tortoises are also sometimes offered in food and traditional medicine shops in Malaysia and China. Export from India and Sri Lanka has been illegal for many years but an illegal trade exists. Fortunately, many of the Indian star tortoises now being offered in the United States and European pet trade are captive-bred hatchlings. ("Manhattan, Kansas", 2001; Das, 1995; Das, 2002; Fife, 2007; Sekhar, et al., 2004)

Economic Importance for Humans: Negative

Indian star tortoises occasionally move into gardens and agricultural areas and feed on crop plants, and are sometimes killed for this reason. However, tortoises are rarely abundant enough to cause significant crop loss. Some farmers simply move tortoises a short distance away. (DeSilva, 2004; Fife, 2007)

Conservation Status

While there are natural threats to Indian star tortoises, such as predation and flooding, none compare to the enormous threat posed by humans. The combined threat of loss of habitat and harvesting for food, as well as the high demand of the exotic pet trade in the U.S., Europe, Middle East, and southeastern Asian countries, has caused this once abundant species to plummet in numbers. ("Honolulu Zoo", 2008; "Manhattan, Kansas", 2001; Das, 1995; Das, 2002; DeSilva, 2004; Edqvist, 2008; Fife, 2007; Gaur, et al., 2006; Sekhar, et al., 2004; Subramanyam, et al., 2006)

An estimate of the yearly toll on the Indian population is 10,000 to 20,000 Indian star tortoises a year disappearing from the wild, with peak collection time between July and August. Hunters collect them from their natural habitat and sell them to middlemen who sell them to smugglers. The use of sea routes has increased as a means to smuggle these animals because security at airports has made it harder to sneak them out by airplane. The smugglers take them out of the country and usually sell them in Bangkok (Thailand) or Malaysia. From there the tortoises are shipped to various markets and dealers in Europe and North America where they can be worth over $150 each. Sadly, these tortoises are hearty in the short term and can often survive at least 15 days without food, making them easier subjects for animal smugglers. Every year, around 3000 Indian star tortoises are recovered from this illegal trade. ("Honolulu Zoo", 2008; "Manhattan, Kansas", 2001; DeSilva, 2004; Edqvist, 2008; Fife, 2007; Gaur, et al., 2006; Sekhar, et al., 2004; Subramanyam, et al., 2006)

Indian star tortoises are also being extirpated through their use as an ingredient in some traditional Chinese medicines. It is believed that they are a source of energy if consumed. Many also believe that keeping these turtles in their home brings good luck. In addition to medicinal consumption, in many parts of India these turtles are used heavily as a food source. Fortunately for the future of this tortoise species, most of this type of consumption is primarily by impoverished people belonging to tribal groups. As mean income increases, there is predicted to be a decrease in consumption of these turtles. ("Honolulu Zoo", 2008; "Manhattan, Kansas", 2001; Edqvist, 2008; Gaur, et al., 2006; Subramanyam, et al., 2006)

Unfortunately for these small tortoises, there has been a boom in the conversion of forest and grassland area to agricultural land, fueled by the ever-growing human population. This has caused huge tracts of land that was once suitable Indian star tortoise habitat to be destroyed completely. ("Honolulu Zoo", 2008; "Manhattan, Kansas", 2001; DeSilva, 2004; Edqvist, 2008; Fife, 2007; Gaur, et al., 2006; Subramanyam, et al., 2006)

A final threat to Indian star tortoises is disease. They are particularly susceptible to pneumonia, respiratory diseases, and parasite overgrowth when stressed by collection, handling, and shipment, often under terrible and inhumane conditions. Many wild-caught specimens sold in the pet trade are doomed to die from (initially) unsuspected disease. (Fife, 2007; Subramanyam, et al., 2006)

Several steps have been taken to conserve this species. In the Indian Wildlife Act of 1972, the possession or trading of Indian star tortoises was made illegal in India. Unfortunately, enforcement of this law is difficult and Indian star tortoises are commonly found for sale in pet shops. They benefit from listing as a CITES appendix II species, which regulates their international trade. ("Manhattan, Kansas", 2001; DeSilva, 2004; Edqvist, 2008; Fife, 2007; "IUCN 2008 Red List - Geochelone elegans", 2008; Subramanyam, et al., 2006)

Presently Indian star tortoises still have a rather wide range, despite the many threats to the species. More research must be conducted while populations are still extant in order to learn more about this fascinating tortoise. It is crucial that this gentle species be adequately protected before the combination of threats it faces drives it to extinction. ("Manhattan, Kansas", 2001; Das, 1995; DeSilva, 2004; Fife, 2007; "IUCN 2008 Red List - Geochelone elegans", 2008; Sekhar, et al., 2004; Tabaka and Senneke, 2006)

Other Comments

This is considered a fairly difficult species to keep and breed in captivity, although captive-bred specimens will certainly be hardier than inevitably stressed wild-caught animals. Useful references on care include information on the World Chelonian Trust Website (Tabaka and Senneke, 2006) and in specific herpetocultural books such as Fife (2007). (Fife, 2007; Tabaka and Senneke, 2006)

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Kyle Bouchard (author), Michigan State University, James Harding (editor, instructor), Michigan State University.

Glossary

acoustic

uses sound to communicate

agricultural

living in landscapes dominated by human agriculture.

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.

carrion

flesh of dead animals.

chemical

uses smells or other chemicals to communicate

crepuscular

active at dawn and dusk

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

desert or dunes

in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

drug

a substance used for the diagnosis, cure, mitigation, treatment, or prevention of disease

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

food

A substance that provides both nutrients and energy to a living thing.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

frugivore

an animal that mainly eats fruit

herbivore

An animal that eats mainly plants or parts of plants.

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.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

infrared/heat

(as keyword in perception channel section) This animal has a special ability to detect heat from other organisms in its environment.

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).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

World Map

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

pet trade

the business of buying and selling animals for people to keep in their homes as pets.

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

riparian

Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).

scrub forest

scrub forests develop in areas that experience dry seasons.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

terrestrial

Living on the ground.

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

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.

vibrations

movements of a hard surface that are produced by animals as signals to others

visual

uses sight to communicate

References

2008. "Honolulu Zoo" (On-line). Star Tortoise. Accessed December 12, 2008 at http://www.honoluluzoo.org/star_tortoise.htm.

International Union for Conservation of Nature and Natural Resources. 2008. "IUCN 2008 Red List - Geochelone elegans" (On-line). Accessed December 12, 2008 at http://www.iucnredlist.org/details/39430.

2001. "Manhattan, Kansas" (On-line). Indian Star Tortoise. Accessed December 12, 2008 at http://www.ci.manhattan.ks.us/DocumentView.asp?DID=1301.

Das, I. 2002. A Photographic Guide to Snakes and Other Reptiles of India. Sanibel Island, Florida: Ralph Curtis Books.

Das, I. 1995. Turtles and Tortoises of India. Bombay: Oxford University Press.

DeSilva, A. 2004. The Biology and Status of the Star Tortoise (Geochelone elegans) in Sri Lanka. Colombo, Sri Lanka: Protected Area Management and Wildlife Conservation Project: Sri Lankan Ministry of Environment and Natural Resources.

Edqvist, U. 2008. "Tortoise Trust" (On-line). Star Tortoise Basics. Accessed December 12, 2008 at http://www.tortoisetrust.org/articles/elegans.html.

Ernst, C., R. Barbour. 1989. Turtles of the World. Washington, D.C.: Smithsonian Institution Press.

Fife, J. 2007. Star Tortoises. Ada, Oklahoma: Living Art Publishing.

Gaur, A., A. Reddy, S. Annapoorni, B. Satyarebala, S. Shivaja. 2006. The origin of Indian Star tortoises (Geochelone elegans) based on nuclear and mitochondrial analysis: a story of rescue and repatriation. Conservation Genetics, 7 (2): 231-240. Accessed December 12, 2008 at http://www.springerlink.com.proxy1.cl.msu.edu/content/pm1106381253lq2l/fulltext.pdf.

Klemens, M. 2000. Turtle Conservation. Washington, D.C.: Smithsonian Institution Press.

Rajaratnam, L. 2008. "Merinews" (On-line). Rampant smuggling of Indian star tortoises. Accessed December 12, 2008 at http://lifestyle.merinews.com/catFull.jsp?articleID=139011.

Sekhar, A., N. Gurunathan, G. Anandhan. 2004. Star Tortoise— A Victim of the Exotic Pet Trade. Tigerpaper, 31 (1): 4-6.

Slavens, F., K. Slavens. 1999. Reptiles and Amphibians in Captivity: Breeding, Longevity, and Inventory. Seattle, Washington: Slaveware.

Subramanyam, G., S. Latheef, B. Prasad, S. Chandrasekara Pillai. 2006. "A DATABASE ON ENDANGERED ANIMALS AT SESHACHALAM HILLS" (On-line). GEOCHELONE ELEGANS. Accessed December 12, 2008 at http://svimstpt.ap.nic.in/EndangeredAnimals/contributors.html.

Tabaka, C., D. Senneke. 2006. "World Chelonian Trust— Star Tortoise Care Sheet" (On-line). Accessed December 23, 2008 at http://www.chelonia.org/Articles/Geleganscare.htm.