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Prehistoric `Lizard of Great Sleepiness' Nearly Extinct in Vietnam and China

Are pet collectors about to drive another species into extinction? This time around it's the prehistoric-looking Chinese crocodile lizard (Shinisaurus crocodilurus).

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


Are pet collectors about to drive another species into extinction? This time around it’s the prehistoric-looking Chinese crocodile lizard (Shinisaurus crocodilurus). According to a paper published in the April TRAFFIC Bulletin, the species has almost vanished from its rapidly shrinking habitats in China and Vietnam due to overwhelming demand from live-animal collectors. Based on extensive field studies by a team of German and Vietnamese researchers, we now know that China only has about 850 crocodile lizards left in the wild, down from an estimated 5,000 in 1991. Vietnam’s population of the lizards, meanwhile, has plummeted to fewer than 100.

Chinese crocodile lizards (which share the same species name regardless of the country they live in) have been protected under various national and international laws for decades, but that apparently hasn’t been enough. The researchers were able to locate dozens of the 40-centimeter-long lizards–known for their muscular tails and dinosaur-like scaly ridges–for sale on Facebook, at reptile fairs and in pet shops, with under-the-table retail prices as high as $1,100.

Many of these sellers claimed to have captive-bred lizards but the researchers expressed doubt, as previous studies have shown that the species has a very low survival rate in captivity. They’re not impossible to breed, and I found several accounts of private collectors breeding them online, but it’s not easy either. So it’s likely some or all of these lizards have been taken from the wild.


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In fact, the vast number of sellers claiming to have Chinese crocodile lizards from the population in Vietnam–which live 500 kilometers away from their slightly more common relatives in China–indicated that many of the animals were sourced from the wild. Crocodile lizards are unfortunately easy to catch. They spend their evenings nesting on branches above pools where they reach a state of “metabolic pause” and sit motionless for hours at a time. That behavior, which makes them easy to catch, earned them the Chinese name “the lizard of great sleepiness,” and the animals were actually used in traditional medicine as a “cure” for insomnia until a few decades ago. Now their rarity makes them more valuable to sell.

Some of this pet trade is legal, or at least appears to be so. The lizards are on Appendix II of the Convention on International Trade in Endangered Species (CITES), which means they can be sold across international borders if they are accompanied by the correct paperwork and permits. Between 1990 and 2013 CITES recorded 850 crocodile lizard sales shipped mostly to Japan, the U.S. and Taiwan. That number, however, hides some oddities. The researchers uncovered 400 supposedly legal, captive-bred lizards shipped in 2005 to Japan and Thailand via Kazakhstan and Lebanon but there is no evidence the seller shipped any more lizards after that point. If the lizards truly were captive-bred and not illegally sourced from the wild, then surely he or she would have many more lizards to sell in the ensuing decade.

Besides illegal captures, the lizards face additional threats in the wild. Their forest habitats are shrinking and their water sources are becoming polluted or disappearing altogether due to dam construction. The sole lizard habitat in Vietnam is surrounded by farmland, leaving the solitary animals nowhere to spread out or evade capture.

TRAFFIC International, the wildlife trade-monitoring network that published the study, has now called on Vietnam to take immediate measures to prevent further losses of their crocodile lizards. The researchers recommend the animals be placed on CITES Appendix I, which would ban all further international trade.

Will that be enough to save the crocodile lizards from extinction? Unfortunately, no matter what happens legally the deck seems stacked against this species. Research published in 2013 predicts that all of the crocodile lizard habitat in China will vanish by the year 2100 as a result of climate change. The Vietnamese territory is already nearly gone. And so by the next century the crocodile lizard might not just look like a dinosaur–it’ll become one.

Photo by UdoSchr?ter. Used under Creative Commons license

John R. Platt is the editor of The Revelator. An award-winning environmental journalist, his work has appeared in Scientific American, Audubon, Motherboard, and numerous other magazines and publications. His "Extinction Countdown" column has run continuously since 2004 and has covered news and science related to more than 1,000 endangered species. John lives on the outskirts of Portland, Ore., where he finds himself surrounded by animals and cartoonists.

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