Geochelone elegans

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.

• Biogeographic Regions
• oriental oriental
  • native native

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.

• Habitat Regions
• tropical tropical
• terrestrial terrestrial

• Terrestrial Biomes
• desert or dune desert or dune
• savanna or grassland savanna or grassland
• forest forest
• scrub forest scrub forest

• Other Habitat Features
• agricultural agricultural
• riparian riparian

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.

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).

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.

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• female larger
• sexes shaped differently

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.

• 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.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

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.

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
• oviparous oviparous

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.

• 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.

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.

• Key Behaviors
• terricolous
• crepuscular crepuscular
• motile motile
• sedentary sedentary
• hibernation hibernation
• daily torpor
• solitary solitary

Home Range

There is no information available on home range size in Indian star tortoises.

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.

• Communication Channels
• visual visual
• tactile tactile
• acoustic acoustic
• chemical chemical

• Perception Channels
• visual visual
• infrared/heat infrared/heat
• tactile tactile
• acoustic acoustic
• vibrations vibrations
• chemical chemical

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.

• Primary Diet
• herbivore herbivore
  • folivore folivore
  • frugivore frugivore

• Animal Foods
• carrion carrion
• insects

• 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.

• Anti-predator Adaptations
• cryptic 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.

• Ecosystem Impact
• disperses seeds

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.

• Positive Impacts
• pet trade pet trade
• food food
• body parts are source of valuable material
• source of medicine or drug source of medicine or drug

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.

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.

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.

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.

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.

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.

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.

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.

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).

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

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

References

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 .

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 .