Chinese crocodile lizard (Shinisaurus crocodilurus)

Also known as: Chinese xenosaur
KingdomAnimalia
PhylumChordata
ClassReptilia
OrderSquamata
FamilyShinisauridae
GenusShinisaurus (1) (2)
SizeTotal length: up to 397 mm (3)

Listed on Appendix II of CITES (1).

The Chinese crocodile lizard is so named for the appearance of its tail, which has an enlarged pair of scales running in two sharply protruding ridges down its length like a crocodile (4). Like the distant relative after which it is named, this lizard is semi-aquatic, and its extremely powerful tail helps make it a strong swimmer (5). Colouration is highly variable, combining shades of grey and brown on the upper surface and yellowish-tan on the lower with distinctive bright orange markings (6) (7). Males are sometimes more colourful than females, often being strikingly adorned with brilliant orange sides and throat, occasionally extending into the side of the head, with these bright colours intensifying during the breeding season (6).

Until recently, this species was thought to be restricted to the Dayao Shan mountain range of the east central Guangxi Province of south-eastern China, but in 2003 a population was also discovered in the Quang Ninh Province of north-eastern Vietnam (3) (7).

At elevations of between 600 and 2,400 ft above sea level, this semi-aquatic lizard inhabits clear shallow pools of slow-moving water with rocky and sandy bottoms with vines dangling above, in secondary evergreen and bamboo forests (8).

Individuals are largely diurnal, with activity concentrated in the morning and evening, but they rarely engage in intense activity. Indeed, dubbed “the lizard of great sleepiness” by local indigenous people, this species often remains motionless for hours on end (3) (9), and can even submerse itself underwater for long periods of time, reducing its respiratory rate (6) (9). This lizard spends much of its time out of the water perched on rocks or branches above slow-moving streams and ponds, and prefers dense vegetation overhanging waterholes for shade and sleeping sites, but will nevertheless retreat to the water when disturbed (3) (6). Food is also obtained from these pools and streams, with the diet consisting of tadpoles, a variety of insects and a considerable amount of caterpillars, as well as dragonfly larvae, grasshoppers and small fish (3) (6).

This solitary species is usually observed with only one animal per pool (7), but individuals may congregate in winter months before hibernating in rock crevices or tree holes from November to March (3) (7). Breeding takes place in July and August (3), with two to seven live young typically born after a gestation period of around 8 to 12 months (6). Young are immediately very active and begin to feed soon after birth (9), and sexual maturity is thought to be obtained within two to three years (6).

The natural habitat of the Chinese crocodile lizard is under attack by extensive deforestation, and illegal logging now sadly threatens the newly discovered Vietnamese population (3) (6). This not only causes the streams and ponds on which the species so heavily relies to dry out, but also reduces ground cover, making the lizard more vulnerable to predation by birds, mammals and humans (6). Its unique and colourful appearance, coupled with its docile nature, have made this lizard a great favourite with collectors, and large numbers were exported for the pet trade in Europe and America in the mid-1980s (3). This species is also still widely used in traditional Chinese medicine, since its ability to remain immobile for hours, occasionally days, led to the belief that it could cure insomnia (5) (6). Thus, by 1999, habitat destruction and hunting had reduced known Chinese population sizes to an estimated 3,000 individuals, with some sub-populations reduced to fewer than just 20 lizards (3). However, comprehensive studies are hampered by the lizard’s secretive behaviour and the rugged terrain of its habitat, and its status therefore remains relatively uncertain (6).

In January 1990, following requests from German conservation authorities, the Chinese crocodile lizard was listed on Appendix II of CITES, which limited the numbers that could be legally exported from China (3) (6). From that time on, virtually no wild-caught specimens have been imported into Europe or the United States (6). The species also now receives full state protection in several areas of China (3). Fortunately, many collectors who obtained imported specimens before restrictions have established captive breeding programmes, helping to contribute to the conservation of the species (3). The North American Regional Studbook for the Chinese crocodile lizard was published in 1995 and 1998 and continues to be maintained at the Fresno Chaffee Zoo (2). This helps preserve genetic diversity within captive populations, which provide a buffer against extinction and may one day be reintroduced back into their native home.

For more information on the Chinese crocodile lizard see:

Authenticated (04/12/2006) by Andy Snider, publisher of the North American Regional Studbook for the Chinese crocodile lizard, and Director of Animal Care and Conservation, Fresno Chaffee Zoo, California.
http://www.fresnochaffeezoo.com/

  1. CITES (May, 2006)
    http://www.cites.org
  2. Snider, A. (2006) Pers. comm.
  3. Bever, G.S., Bell, C.J. and Maisano, J.A. (2005) The Ossified Braincase and Cephalic Osteoderms of Shinisaurus crocodilurus (Squamata, Shinisauridae). Palaeontologia Electronica, 8(1). Available at:
    http://palaeo-electronica.org/2005_1/toc.htm
  4. Saint Louis Zoo (June, 2006)
    http://www.stlzoo.org/animals/abouttheanimals/reptiles/lizards/chinesecrocodilelizard.htm
  5. Detroit Zoo (June, 2006)
    http://www.detroitzoo.org/zoo/index.php?option=content&task=view&id=526&Itemid=557
  6. AnimalNetwork.com - Hoffmann, E.G. The Chinese Crocodile Lizard. (June, 2006)
    http://www.animalnetwork.com/reptiles/library/articleview.asp?Section=&RecordNo=2468
  7. The Columbus Zoo and Aquarium (June, 2006)
    http://www.colszoo.org/animalareas/reptiles/crocliz.html
  8. Sedgwick County Zoo (June, 2006)
    http://www.scz.org/animals/l/clizard.html
  9. Indiana University (June, 2006)
    http://www.cogsci.indiana.edu/farg/harry/bio/zoo/shinisau.htm