- Status: Critically endangered
- Known as: Ploughshare Tortoise, angonoka, angonoka tortoise, Madagascar tortoise, Madagascar angulated tortoise.
- Estimated numbers left in the wild: 600.
Ploughshare tortoises are smallish land tortoises with high-domed, brown shells, measuring around 40 centimeters long. Males weigh a bit over 10 kilograms, while females average 8.8 kilograms – the sexes can often be distinguished visually by size.
One of the plates, or scutes, of the lower shell projects out and up between the front legs, vaguely resembling a ploughshare and giving the species its name.
The tortoises live on land and feed on all kinds of plants, with grasses forming most of their diet. The reptile seems to favor the types of grass that grow in bamboo scrub.
They will eat dead bamboo leaves but seem to avoid the fresh shoots and leaves completely. Herbs and shrubs may also be consumed, and the tortoises will eat the droppings of mammals living in their area.
When breeding is occurring, male ploughshare tortoise “joust” with their ploughshare scales, attempting to hook the ploughshare under the other tortoise’s shell to flip him over. The males also ram each other with the enlarged scales and can be quite aggressive when vying for females.
The female buries up to seven clutches of eggs per breeding season, leaving the young to hatch at the start of the rainy season and fend for themselves. Sexual maturity is not achieved for two decades, an unfortunate trait for a highly endangered animal.
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The ploughshare tortoise is found only in a sixty square kilometer area in north-western Madagascar, around Bally Bay. The terrain and flora here are mixed, including mangrove swamp, savannah, bamboo scrub, and deciduous forest. Most of the region is within 50 meters of sea level. The tortoises prefer dense bamboo thickets.
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Extinction is looming large in the ploughshare tortoise’s future and may occur in no more than a decade. The species cannot replenish itself rapidly due to its slow reproductive cycle.
Hunting by humans is one major pressure on this tortoise, but even more, the damage is being done to these reptiles by the bush pig. People and prey introduced this swine species on both the eggs and young of the tortoise.
Madagascar farmers often carelessly start more or less uncontrolled fires to clear brush for agriculture, and these fires can spread and destroy ploughshare tortoise habitat and kill the animals themselves.
Additionally, the illegal global pet trade generates a high demand for captured tortoises, which are usually small, young individuals needed to build the population.
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Firebreaks created along the fringes of the tortoises’ home range are one of the more successful conservation measures that have been undertaken, greatly reducing the impact of runaway agricultural fires.
A captive breeding program has successfully produced hundreds of tortoises, despite dozens being stolen during a major break-in by robbers who then sold the animals for pets. A park is also planned in the Baly Bay area, but the prospects for the ploughshare tortoise remain bleak, and it may be too late to salvage the species.
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Do you know of or are you a part of an organisation that works to conserve the Ploughshare Tortoise, then please contact us to have it featured on Our Endangered World.