Why are environmentalists putting graffiti on tortoises?

(CNN)Madagascar is home to the most endangered tortoise on the planet: The ploughshare. Collectors will pay tens of thousands of dollars on the black market for these rare animals. Conservationists have come up with an extreme solution: Desecrate the shell.

"People poach ploughshare tortoises for their value as pets," says Eric Good, founder and president of the Turtle Conservancy.
"Like coin collectors who want a mint coin, collectors want a perfect tortoise, so by defacing the animals we make them less appealing to buyers," he adds.
    Goode has been working the Madagascan government and international and local conservationist groups to implement the program of "tattooing" the animals.

    In high demand

    The shape and color of ploughshares (the spectrum goes from light brown to golden) has made it popular in Asia, particularly in China, Indonesia and Thailand, notes Goode, who says collectors will typically pay $2,500 for a hatching and as much as $50,000 for an adult tortoise.
    The animals also face threat from local fires and the eating habits of the bush pig, who likes to feat on both the eggs and fledglings. Due to their dense living quarters, putting human trackers on the beasts has proven difficult, making it hard to estimate how many are left.
    "Nobody really knows how many are in the wild," admits Goode.
    "There may be 200 to 500 left, but it's probably less than that."
    Matters are not helped by the fact that the tortoise's breeding cycle is painstakingly slow (it takes 20 years for the animal to reach breeding age), and that females don't produce enough eggs to replenish the species quickly.

    Urgent measures

    The move by conservationists to deface the tortoises' shells to solve the problem is, admittedly, controversial, but, says Goode, ultimately necessary.
    "Cutting off rhino horn to protect the rhino is similar," he explains.
    "We are having to take more extreme measures."
    The process is not too invasive. The letters MG and then a serial number is engraved into the shell of the adult, which has keratin thick enough to withstand the procedure. But for young tortoises and hatchlings (the easiest targets for poachers), carving into the shell would be a painful procedure. As a result, conservationists are starting to tattoo these animals instead. Goode explains that this has been done with some success in Burma.
    "The Burmese star tortoise was effectively extinct. All remaining tortoises were tattooed with a religious symbol, sacred to the Burmese people, which reduced the numbers poached," he explains.