southern coast of Madagascar
This tortoise inhabits arid to semi-arid areas in sandy soil where succulents and thorny shrubs dominate the vegetation.
Fully grown, the species rarely reaches more than six inches in length. The shell is oblong, highly curved and widens toward the rear. The shell has five to eight yellow lines radiating out from a yellow center, against a dark brown or black background. The tortoise gets its name from these web-like yellow patterns marking the back of its shell. The shell on the underside of the tortoise, known as the plastron, is totally without markings and the anterior lobe can close completely to the touch carapace.
The head is dark and speckled with several yellow spots, and the legs and tail are brown. The tail of the male is longer and thicker than that of the female, and has a harder tip. Males and females are also be identified by the generally larger size of the females.
With the beginning of the dry season in April, most spider tortoises bury themselves deep into the sand and estivate for the duration of the drier weather. Estivation is a state of dormancy similar to winter hibernation, but in estivation, tortoises do not sleep all the time and may surface if the conditions are right. However, during the months of April to November, the tortoises mostly remain inside their favorite burrows sleeping as an energy-saving tactic for when vegetation and water are sparse.
The spider tortoise is most active during the wet season between November and April. It emerges with the rains, feeding on the new plants that grow after the rains. They are crepuscular, active at dawn and dusk, with most activity in the mornings after sunrise.
Spider tortoises will remain dormant in burrows in the sand for as long as six to eight months out of the year. During the four to six months they are active, the females lay a clutch with a single egg. Females may lay up to three clutches per year in captive breeding programs, whether this reflects true behavior in the wild is not clear.
The young then remain in a diapause (held in stasis without developing), within the egg until favorable conditions return the following year. The eggs hatch after 220 to 250 days. The tiny hatchlings measure just one and a half inches long at hatching. Spider tortoises reach sexual maturity between six and twelve years of age.
Interesting Facts:• There are three, geographically separate subspecies of spider tortoise in Madagascar. • Radiated tortoise lives alongside this tortoise, with spider tortoises often sharing the much larger radiated tortoise’s burrow. • The spider tortoise is the only tortoise species with a hinged plastron. This unique character makes it coveted by collectors and as a result, it is illegally traded within the international pet market.
Spider tortoises are critically endangered due to habitat loss and the illegal pet trade. Utah’s Hogle Zoo staff works in Madagascar conducting field research and education programs. The Zoo also participates in the Madagascar Spider Tortoise Species Survival Plan®, a shared conservation effort by zoos throughout the Association of Zoos and Aquariums.
This species has numerous conservation challenges to face. Loss of habitat is at the top of the list. Human-caused fires, conversion to agriculture, charcoal production, firewood collection and invasive plants have all taken their toll on the habitat. These threats, combined with Madagascar’s growing population, all play a role in the loss of habitat necessary for the tortoises’ survival.
Likewise, illegal harvesting for the pet trade affects them. Their small size and attractive shell makes spider tortoises extremely popular with exotic pet owners from around the world. Despite the ban in international trade in this species, they are still collected in large numbers and smuggled out of Madagascar to support the pet trade. A small number are also collected for local consumption, but the impact of this on the species is minute in comparison to the threats of habitat loss and international trade.
The effort to save endangered species requires cooperation and support at the international, national, regional and individual levels. You can help. Support Utah’s Hogle Zoo and other conservation organizations. Share your concerns about wildlife with your local and state representatives.
If you are considering a tortoise as a pet, do your homework. The Zoo does not recommend reptiles as pets for most people, as they require very specialized diets and environments, and often live a very long time. In the case of a tortoise, it could be a 50 to 100 year commitment! If you do choose to care for one, learn about its needs and be sure it was captive-bred.
|Did YOU Know?|
|The spider tortoise is one of the smallest tortoises in the world.|
|Length:||Up to 6 inches|
|Weight:||7 to 14 ounces|
|Average Lifespan:||in the wild, the average lifespan is unknown; 50 + years in zoological institutions|
|Wild Diet:||grasses, young leaves, roots and cow dung with insect larvae.|
|Zoo Diet:||vegetables and tortoise biscuits|
|Predators:||birds of prey, fossa and snakes|
|This is an ssp animal|
|USFWS Status:||under review|
|Where at the Zoo?||Small Animal Building: Desert Zone|