Chinese Water Dragons: Bound to theStream, Taken From It by Hand
In the forest streams of central Vietnam, the rong dat lives within a jump of running
water, resting on branches above the current and escaping by dropping into it. That
attachment to one narrow strip of habitat also makes it easy to collect, and US import
records alone list more than 1.4 million live animals between 1999 and 2018.
In 2016, hunters in three hill districts of Thua Thien Hue, the province north of Da Nang now administered as Hue city, took about a tonne of Chinese water dragons (Physignathus cocincinus) from the forest streams: more than 2,000 animals, by the reckoning of the researchers who recorded the catch [1],[2]. When the same team surveyed stream sections in those districts in 2016 and 2017, its estimate for all the surveyed sites together came to between 232 and 250 [1].
The surveys covered only part of the province, but the authors argue that an animal so tightly bound to small streams is unlikely to be much more numerous than their count suggests [1]. The two numbers frame the whole story. An animal that lives along a thin line of water is being taken from that line by hand, for local kitchens and the international pet trade [1],[3], and where the forest along a stream is broken, the harvest weighs more heavily on what remains [1].
• Green adults, banded young and two Vietnamese names
Adult water dragons are hard to mistake for anything else in a Vietnamese forest. They are green to brownish-grey, with a body and tail flattened from side to side, a crest running from the neck down the back and a tail ringed with dark bands; the scales of the jaw and cheek are pale, and a dark stripe runs from behind the eye to the ear [3]. The published maximum is about 250 mm from snout to vent and 900 mm with the tail [3]. Animals measured for a study in Thua Thien Hue averaged 195mm in body length and 355 g, the heaviest weighing 650 g [4]. The animals photographed for this article in central Vietnam show all of these features.
Young animals look like a different species. Hatchlings measure 45 to 53 mm from snout to vent [3], and juveniles carry bright stripes along the flanks that fade with age [3]; in the young photographed for this article, the body is brown and barred while the head and lips are already green. Much of what separates grown animals from young ones is sexual. Crests develop with age and are most pronounced in males, which also grow larger heads and swollen cheeks [3]. A 2024 study of 90 wild adults in Vietnam found males larger and heavier, with longer head and back crests, a difference its authors attribute to competition between males for territory, food and mates, and to female choice [5].
The animal has two Vietnamese names. Rong dat, ‘earth dragon’, is the one used in scientific and official documents, from the CITES proposal that Vietnam co-sponsored to the national list of protected forest animals issued in 2025 [3],[6]. Ky tom is the name in local reporting from the uplands of Quang Ngai and Lam Dong, and one Quang Ngai writer calls rong dat a playful name for the ky tom [7],[8].
The species ranges from southern China through Vietnam, Laos and Cambodia to eastern Thailand, and a reported occurrence in Myanmar has not been confirmed [3]. In Vietnam it has been recorded from the northern mountains to the south, including Thua Thien Hue, Da Nang and Quang Nam in the centre [3], a province since merged into Da Nang [2]. That is as fine as this article goes: locations are given at province level only, a deliberate choice for an animal this much in demand. Even that overstates the ground it uses. Tied to streams, it probably occupies less than 500 square kilometres, according to the Red List assessment [3],[9].
The Chinese water dragon’s range at country and province level (schematic). Vietnam, in darker green, has records from north to south; the species occurs throughout Laos and Cambodia in suitable habitat; hatching marks provinces with records in eastern Thailand and southern China [3],[9]. A reported occurrence in Myanmar is unconfirmed, and introduced populations are not shown [3]. Tied to forest streams, the species is thought to occupy less than 500 square kilometres of this area [9]. Da Nang is marked for orientation only; no survey or collecting sites are shown. Boundaries: Natural Earth [10]; Truong Son range drawn schematically.
• A life lived within a jump of the water
The water dragon’s whole life is organised around a stream. Survey teams in Thua Thien Hue recorded it only at the stream bank, close to the water or above it, along rocky streams 1 to 12 m wide with dense vegetation along and over the channel [1]. Across its range it keeps to streamside forest between about 43 and 820 m above sea level, and a dense canopy beside the water appears to be essential [3]. Adults usually perch more than 3 m above the water, while juveniles and subadults stay lower, mostly under 2 m [3]. At night the animals sleep on branches over the stream [1].
The perch over the water is also the way out. A disturbed water dragon drops into the stream or runs off upright on its hind legs into the undergrowth, and it swims and dives well [3]. The arrangement needs both parts: an escape that works by dropping into water needs water beneath the branch, and a stream without overhanging branches offers nowhere to perch above it.
Why the water dragon needs both a stream and branches over it (schematic cross-section). Adults usually perch more than 3 m above the water, juveniles and subadults mostly under 2 m; animals sleep on branches over the stream and escape by dropping into the water [1],[3]. On the right, clearance for roads and logging removes the overhang [1], and altered flows below dams, with reported droughts, floods and bank erosion,
change the stream beneath it [11],[12]. Heights and stream widths from surveys in Thua Thien Hue; lizards enlarged for clarity.
The animal does not travel far for either: water dragons in central Vietnam moved over an average range of just 4.7 m [3]. Their food comes from the same narrow strip. A study in Thua Thien Hue identified 30 kinds of food, chiefly insects (56 percent) and earthworms (24 per cent) [4]. Sources disagree on plants. A 2018 stomach-content study by Nguyen and colleagues in the same province found only a small share, while Thomas Ziegler’s 2002 study of a lowland reserve elsewhere in Vietnam put plant food at up to a third of the diet of mature animals [3]: a different place, and an adults-only figure. In summer, the Hue stream corridors measured 29.1 °C by day and 25.7 °C at night [3].
4.7 m - average movement range of water dragons followed in central Vietnam
That fidelity leaves the species exposed to whatever happens along streams. In Thua Thien Hue, a highway built through the hills cleared large parts of the forest and fragmented forest streams [1]. In the Vu Gia–Thu Bon basin of former Quang Nam,
now part of Da Nang [2], a strategic assessment of the provincial hydropower plan counted 8 major and 34 minor developments on a single river system and warned that they would degrade or alter aquatic habitats [11]. For a sedentary animal that cannot move long distances, such fragmentation is a serious threat in its own right [3].
• Fast-growing young, few breeding adults
The water dragon’s problem is not a slow start in life. In Thua Thien Hue, clutches of 7 to 15 eggs have been recorded, taking 68 to 78 days to hatch [4]; compilations of field and captive sources give wider ranges (Figure 3) [3]. The young grow fast. Finding juveniles dominant in April and subadults in June, the Hue researchers concluded that juveniles reach subadult size in about two months [1]. In captivity, water dragons mature at 6 to 12 months and a snout–vent length of about 150 to 170 mm, females can lay several clutches a year, and individuals live 15 to 25 years [3].
What the wild population lacks is adults. In the Hue surveys, adults made up about a fifth of the animals counted: 21 per cent in April and 17 per cent in June [1]. They are also what hunters want. Interviews with 21 hunting groups found adult lizards
heavily collected, by hand and in traps, from February to October, with the largest catches in May and June [1], a season that spans April, when females’ ovaries are heaviest [4]. Most hunters prefer adult males because they are bigger [1], and the 2024
study reported that hunters and traders favour males because they sell for more, pointing to earlier surveys that recorded a sharp fall in adult males during the hunting season [5].
17–21% - share of adults among the water dragons counted in the Thua Thien Hue surveys
The export trade takes the other end of the life cycle. Although the species is widely bred in captivity, the Red List assessment notes that juveniles are taken from the wild for export, especially from Vietnam, so that food and pet harvests together reach
every life stage [9]. The Hue researchers warn that a continuing loss of mature animals could reduce breeding capacity and genetic diversity [1]. The one surveyed area with hardly any habitat damage held the most animals and the highest share of adults, which the authors read as a sign that intact habitat can buffer the harvest [1].
Harvest reaches every life stage. The bar follows snout–vent length using the size classes of field surveys in Thua Thien Hue, where adults were 17–21 per cent of the animals counted [1]. Egg data come from a study in the same province and from compiled field and captive sources [3],[4]; hatchling size, maturity and lifespan come from captive animals, the only source for age at maturity [3]. Growth to subadult size in about two months is the field team’s reading of their seasonal counts [1]. Pet-trade sizes are those of wild-caught animals offered in Germany in 2020 [3]; juveniles are taken from the wild for export [9]; adults, especially large males, are the main target of the food harvest [1],[5].
• Wanted alive: what the trade records show, and what they miss
Demand comes from two directions. At home the water dragon is food: animals caught in Thua Thien Hue were sold in local markets and passed on to restaurants [1]. Abroad it is wanted alive for its attractive appearance and semi-aquatic habits, the reasons the CITES proposal gives for its place in the pet trade [3]. Researchers documented 51 domestic dealers and nine online pet shops trading it in Vietnam from 2015 onwards [13].
The recorded international trade is large. United States import records list more than 1.4 million live water dragons between 1999 and April 2018, almost 95 per cent declared wild-caught and 99.8 per cent from Vietnam; imports averaged about 81,000 a year between 2002 and 2011 [3]. For 2011 to 2020, US records show just over 560,000 live animals, 94 per cent of them wild-sourced [14]. The European Union, which has tracked imports since 2010, recorded 74,124 live animals between 2010 and 2019, about 90 per cent of them exported by Vietnam [3].
1.4 million - live water dragons in US import records, 1999 to April 2018, almost 95 percent declared wild-caught
These are records of legal imports into two markets, not counts of animals taken. They leave out everything eaten in Vietnam or traded within Asia, and the Hue team described even the EU figures as only a visible fraction of the real international
trade [1]. They are a floor, not a total.
The declared sources need the same caution. Water dragons breed readily in captivity, yet most traded animals are still wild-caught, because collecting them remains easier and cheaper [3]. In the EU records, 83.5 per cent of imported animals had no stated origin, 9.2 per cent were declared captive-bred and 7.3 per cent wild [3]. Almost 7,000 of those captive-bred declarations came from Vietnam, where there is no evidence of breeding facilities able to supply such numbers [3]. The Hue team found that local operations once rearing water dragons for restaurants had closed, because collecting wild animals was more convenient, and concluded that most traded animals of unknown origin are probably wild [1].
Declared origin of live Chinese water dragons in recorded imports. Bars show shares by declared source in three datasets: US imports from 1999 to April 2018 (more than 1.4 million animals; US LEMIS records as reported in the CITES listing proposal) [3]; US imports from 2011 to 2020 (just over 560,000; IUCN and TRAFFIC analysis) [14]; and EU imports from 2010 to 2019 (74,124; UNEP-WCMC records under the EU’s Annex D) [3]. The species entered the CITES Appendices only in 2023, so no year shown falls under CITES permits. Recorded imports are not total offtake: they exclude animals eaten or traded within Asia, and sources are as declared in the records.
Harvest and habitat loss work together rather than side by side. In Thua Thien Hue, the road building that fragmented streams also opened the forest: the researchers found that almost every part of two protected areas in the province could now be reached easily, which had already made illegal logging easier [1]. The districts where both harvest and habitat damage were rated high had the smallest subpopulations and the fewest adults [1].
• What protection covers, and where it stops
Formal recognition has tightened in stages. Vietnam’s Red Data Book listed the water dragon as Vulnerable in 2007 [1], on an estimated 20 per cent decline over ten years [3]. The IUCN Red List assessed it as Vulnerable in May 2017, in an assessment
published in 2019, and judged the population to be in decline: harvesting is heavy across most of the range, declines are suspected, on a precautionary basis, to exceed 30 per cent over three generations, and their causes, harvest and habitat loss, have not ceased [3],[9]. In November 2022, a proposal from Vietnam and the European Union to list it in CITES Appendix II passed in committee by 81 votes to 27, with 20 abstentions [15]; the listing took effect on 23 February 2023 [16].
Appendix II is not a ban. It requires an export permit, which may be issued only when the exporting country’s scientific authority finds that the export will not harm the species’ survival in the wild and its management authority finds that the animals were legally obtained [17]. It governs trade across borders; the food trade in Thua Thien Hue’s markets and restaurants [1] is a matter for national law.
National law followed later. When the CITES listing was proposed, the species was not covered by any Vietnamese wildlife protection law, and collection without a permit was restricted only inside protected areas [3]. Since June 2025, Circular 27/2025/TT-BNNMT has placed it in Group IIB of Vietnam’s list of endangered, precious and rare forest animals, the second of the list’s two tiers, and not among the species given priority protection [6].
Protected areas have not kept the harvest out. The Hue surveys were carried out inside two nature reserves and a national park, and harvesting was recorded in every district surveyed [1]. Because water dragons live both inside and outside protected areas, rangers find the origin of an animal in trade very hard to establish [3], and the IUCN and TRAFFIC analysis for CITES describes enforcement of the protected-area rule in Vietnam as difficult [14].
What the record does not yet show
How many water dragons live along the streams around Da Nang itself? At what age does a wild animal first breed, and what does the barred coat of the young do for it? How many are eaten in Vietnam each year, a trade no export permit records? And now that exports need CITES permits, how many animals declared captive-bred come from breeding facilities rather than streams? The answers would show whether the new protections are reaching the water.
• An animal that cannot leave its stream
Everything the rong dat does happens within a few metres of running water. It feeds within reach of the bank, rests on branches above the current, sleeps over it at night and drops into it when threatened. That fits it closely to a forest stream,
and it also makes it easy to take: an animal that stays put along a single line of water is, in the words of the CITES proposal, ‘very easy to collect’ [3]. Its future in central Vietnam will be settled along those streams, by whether they keep their forest and
whether enough adults remain on the branches above them to breed.
Sources
1. Nguyen, T.Q., Ngo, H.N., Pham, C.T., Van, H.N., Ngo, C.D., van Schingen, M. & Ziegler, T. First population assessment of the Asian Water Dragon (Physignathus
cocincinus Cuvier, 1829) in Thua Thien Hue Province, Vietnam. Nature Conservation 26: 1–14. Pensoft, 2018.
https://natureconservation.pensoft.net/article_preview.php?id=21818 (accessed 18 September 2026).
2. National Assembly of Vietnam. Resolution 202/2025/QH15 on the reorganization of provincial-level administrative units (English translation). LuatVietnam,
(accessed 18 September 2026).
3. European Union and Viet Nam. CoP19 Prop. 14: Proposal to include Physignathus cocincinus in CITES Appendix II. CITES Secretariat, 2022.
https://cites.org/sites/default/files/documents/E-CoP19-Prop-14.pdf (accessed 18 September 2026).
4. Ngo, D.C., Tran, T.M.H. & Tran, D.V.H. Mot so dac diem sinh hoc cua Rong dat o Nam Dong, Thua Thien Hue [Some biological characteristics of the green water
dragon in Nam Dong, Thua Thien Hue province]. Tap chi Nghien cuu va Phat trien 6(65): 84–89. Vietnam Journals Online, 2007.
https://vjol.info.vn/ncpt-hue/article/view/7035 (accessed 18 September 2026).
5. Vietnam Academy of Science and Technology. Luong hinh gioi tinh o loai Rong dat, Physignathus cocincinus, o Viet Nam: nguyen nhan gian tiep dan den san bat
chon loc theo gioi tinh [research summary of Ngo, H.N. et al., Salamandra 60, 2024]. VAST, 2024. https://vast.gov.vn/en/tin-chi-tiet/-/chi-tiet/luong-hinh-gio
i-tinh-o-loai-rong-%C4%91at-physignathus-cocincinus-o-viet-nam-nguyen-nhan-gian-tiep-dan-%C4%91en-san-bat-chon-loc-theo-gioi-tinh-133831-403.html
(accessed 18 September 2026).
6. Ministry of Agriculture and Environment of Viet Nam. Circular 27/2025/TT-BNNMT, Annex I: List of endangered, precious and rare species (24 June 2025). MAE,
2025. https://www.mae.gov.vn/noidung/Lists/VBQPPL/Attachments/576/27-bnnmt-kem.pdf (accessed 18 September 2026).
7. VietNamNet. Ly ky chuyen san rong dat o vung rung nui Tay Tra. VietNamNet, n.d.
https://vietnamnet.vn/ly-ky-chuyen-san-rong-dat-o-vung-rung-nui-tay-tra-459526.html (accessed 18 September 2026).
8. VietNamNet. San rong dat tren cao nguyen. VietNamNet, n.d. https://vietnamnet.vn/san-rong-dat-tren-cao-nguyen-479810.html (accessed 18 September
2026).
9. Stuart, B., Sumontha, M., Cota, M., Panitvong, N., Nguyen, T.Q., Chan-Ard, T., Neang, T., Rao, D.-q. & Yang, J. Physignathus cocincinus. The IUCN Red List of
Threatened Species 2019: e.T104677699A104677832 (assessed 24 May 2017). IUCN, 2019. https://www.iucnredlist.org/species/pdf/104677832 (text read
from the copy at https://www.researchgate.net/publication/336171101_Physignathus_cocincinus_Red_List_Data) (accessed 18 September 2026).
10. Natural Earth. Admin 0 Countries (1:50m) and Admin 1 States and Provinces (1:10m), public-domain map data. Natural Earth via the natural-earth-vector
repository, n.d. https://raw.githubusercontent.com/nvkelso/natural-earth-vector/master/geojson/ne_50m_admin_0_countries.geojson (accessed 18
September 2026).
11. International Centre for Environmental Management (ICEM). Biodiversity and Hydropower in Vietnam: policy brief, Volume III. ICEM, n.d.
(accessed 18 September 2026).
12. Tropenbos International. Hydropower plant development in Viet Nam’s Central Zone and Central Highlands: a trade-off. Tropenbos International, n.d.
(accessed 18 September 2026).
13. Gewiss, L.R., Ngo, H.N., van Schingen-Khan, M., Bernardes, M., Rauhaus, A., Pham, C.T., Nguyen, T.Q. & Ziegler, T. Population assessment and impact of trade
on the Asian Water Dragon (Physignathus cocincinus Cuvier, 1829) in Vietnam. Global Ecology and Conservation 23: e01193. Elsevier, 2020.
https://www.sciencedirect.com/science/article/pii/S2351989420307344 (accessed 18 September 2026).
14. IUCN and TRAFFIC. IUCN/TRAFFIC Analyses of the Proposals to Amend the CITES Appendices at the 19th Meeting of the Conference of the Parties: CoP19 Prop.
14. IUCN and TRAFFIC, 2022. https://www.researchgate.net/publication/363519713_IUCNTRAFFIC_Analyses_of_the_Proposals_to_Amend_the_CITES_Appe
ndices_at_the_19th_Meeting_of_the_Conference_of_the_Parties (accessed 18 September 2026).
15. IISD Earth Negotiations Bulletin. Daily report for 21 November 2022: CITES CoP19, Committee I. IISD, 2022.
https://enb.iisd.org/convention-international-trade-endangered-species-wild-fauna-flora-cites-cop19-daily-report-21nov2022 (accessed 18 September
2026).
16. CITES Secretariat. Notification to the Parties No. 2023/020: Amendments adopted at CoP19 enter into force on 23 February 2023. CITES, 2023.
https://cites.org/sites/default/files/notifications/E-Notif-2023-020.pdf (accessed 18 September 2026).
17. U.S. Fish and Wildlife Service. CITES Appendix II fact sheet. USFWS, 2024.
https://legacy.fws.gov/sites/default/files/documents/2024-04/factsheet-cites-appendix-ii-2024.pdf (accessed 18 September 2026).
Comments