The Chinese crocodile lizard spends much of its time in shallow water or in overhanging branches and vegetation, where it hunts its prey of insects, snails, tadpoles, and worms.
[6] It is the only living member of Shinisauria, a clade of lizards whose fossil record extends back to the Early Cretaceous, over 120 million years ago.
For the Chinese crocodile lizard (as an endangered species), the gut microbiota is an area of concerned study and interest; greater understanding of their diet and dietary functions help contribute to a more stable international, and (ultimately) wild, population.
For mature animals, the crocodile lizards consume prey opportunistically, from earthworms, centipedes, millipedes, and beetles to the larvae from Lepidoptera.
[16] Surviving subpopulations of Chinese crocodile lizards primarily occupy isolated fragments of land in Guangxi and Guandong provinces of southeastern China.
The Vietnamese subspecies is only found on Yên Tử Mountain in Quảng Ninh and Bac Giang provinces of northeastern Vietnam.
[10] The species lives in a relatively cool, monsoonal climate at moderately high elevations, 200–1,500 meters (660–4,920 ft) above sea level.
Shinisaurus crocodilurus utilize tree holes, rocks, vegetated perches as shelter and are rarely found exposed on the forest floor.
[12] Shinisaurus (literally "Shin's lizard") honors the biologist Sin Shu-szi [zh] (Chinese: 辛树帜; pinyin: Xīn Shùzhì), a member of a joint Chinese-German expedition that discovered this species (as well as the frog Quasipaa shini).
[22][23] They were named as a new subspecies (S. crocodilurus vietnamensis) in 2016, in light of several ecological, genetic, and morphological distinctions relative to the Chinese subpopulations.
Genetic studies of captive individuals indicate that Shinisaurus crocodilurus is split into four clades, three of which originated in China and one of which corresponds to the Vietnamese subspecies.
[25] However, wild individuals and local breeding programs in China appear show low genetic diversity between subpopulations.
Removal of broadleaf evergreen foliage makes streams more volatile, leading to flooding and drying cycles which are unsuitable for the lizards.
Other sources of habitat loss include mining pollution, small-scale farming, and dam construction leading to water flow changes.
[6] Another prominent threat is poaching for the pet trade, meat, and traditional Chinese medicine as a claimed cure for insomnia.
In some cases, the number of traded animals approaches or exceeds the wild population estimate, suggesting the presence of undiscovered subpopulations known only to collectors.
[32][5][30] The sedentary lifestyle of the lizards eases collection, and poaching by local citizens is further incentivized by lucrative selling prices offered by dealers.
The striking appearance of Shinisaurus crocodilurus has fueled the interest of reptile hobbyists in Europe and North America, though most captive individuals are slow to mature and did not live long before knowledge on their care was widely known.
[6][26] Closely monitored breeding programs have been set up in Daguishan and Luokeng nature reserves, in the hopes of eventual reintroduction to other protected areas.
Brochures, posters, and petitions developed with the help of the Cologne Zoo have attempted to spread awareness on the subspecies and its conservation, for the sake of both local citizens and Vietnamese government officials.
[32][35][5] The species currently receives no special treatment under Vietnamese law, though hunting animals within protected areas without a permit is illegal.
[12][11] Isotope analyses have shown that the scales of captive bred individuals are enriched in Carbon-13 and Nitrogen-15, likely a result of being fed with protein-loaded feeding insects.