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Brief CommuniCation
https://doi.org/10.1038/s41559-019-1027-7
1Global Wildlife Conservation, Austin, TX, USA. 2Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany. 3Southern Institute of Ecology,
Vietnam Academy of Science and Technology, Ho Chi Minh City, Vietnam. 4NCNP, Ninh Thuan Province, Vietnam. 5Borneo Futures, Bandar Seri Begawan,
Brunei Darussalam. 6University of Queensland, Brisbane, Queensland, Australia. 7Center for the Conservation of Tropical Ungulates, Punta Gorda, FL, USA.
8These authors contributed equally: An Nguyen, Andrew Tilker. *e-mail: atilker@globalwildlife.org
In an age of mass extinctions, confirming the survival of lost
species provides rare second chances for biodiversity con-
servation. The silver-backed chevrotain Tragulus versicolor,
a diminutive species of ungulate known only from Vietnam,
has been lost to science for almost three decades. Here, we
provide evidence that the silver-backed chevrotain still exists
and the first photographs of the species in the wild, and urge
immediate conservation actions to ensure its survival.
The Greater Annamites Ecoregion of Vietnam and Lao PDR
contains one of the highest concentrations of endemic mammal
species found anywhere in a continental setting1; it has a par-
ticularly diverse suite of endemic ungulates1. Unfortunately, the
distribution and population sizes of its endemic ungulate species
have been severely reduced from historical levels due to anthro-
pogenic pressures2–4. Habitat loss has been a major factor in these
declines1, especially in Vietnam5, but a more substantial threat to
the region’s ungulates is the widespread and intensive hunting,
which supplies the thriving wildlife trade in Indochina6,7. Hunting
of terrestrial mammals in the Annamites is primarily accomplished
by the setting of indiscriminate wire snares8,9. Snaring is almost
ubiquitous across the Annamites and has resulted in widespread
‘empty forest syndrome’10. Exceptionally high levels of snaring have
driven two endemic ungulates, the saola Pseudoryx nghetinhensis
and the large-antlered muntjac Muntiacus vuquangensis, to the
brink of extinction2–4.
Among the least-known ungulates in the Greater Annamites
Ecoregion is the silver-backed chevrotain T. versicolor11. The silver-
backed chevrotain was first described in 1910 from four specimens
that were obtained near the city of Nha Trang, Vietnam12 (Fig. 1).
The exact localities for the specimens were not provided in the
original publication12, possibly because they were acquired in trade.
Several morphological features distinguish the silver-backed chev-
rotain from the more widespread lesser chevrotain Tragulus kanchil.
The most distinctive external characteristic of the silver-backed
chevrotain is its unique two-tone pelage coloration, with an ocher-
ous-buff anterior and a silver or grey posterior12–15. The grey hairs
are conspicuously tipped with white, giving the posterior a grizzled
appearance13. Another distinguishing characteristic is the absence
of the dark transverse throat stripe that is present in the lesser chev-
rotain. In the silver-backed chevrotain, the ocherous throat lines
converge but do not touch; the white ventral coloration is therefore
contiguous from the throat to the underbelly13–15.
Other than the four specimens that were used to describe the
species, only a single verifiable record exists11. In 1990, a joint
Vietnamese–Russian expedition in the Gia Lai province obtained a
hunter-killed chevrotain in the vicinity of Dak Rong and Buon Luoi
that was later identified as silver-backed chevrotain13. The specimen
shows the pronounced bi-coloration and non-convergent throat
markings that are characteristic of the species (Fig. 2a). Notably, an
additional 24 chevrotain specimens were collected from the area
between 1978 and 1993 as part of the joint expeditions, but there are
no additional silver-backed chevrotain records13. The Gia Lai speci-
men provides limited insights into the ecology of the species. The
area that the specimen was recorded from was described as mature
lowland semi-evergreen tropical forest13. The record suggests sym-
patry with the lesser chevrotain13, although locality information is
not precise enough to indicate syntopy11. However, the most impor-
tant consequence of the Gia Lai specimen was the confirmation that
the silver-backed chevrotain was still extant13,16.
Following the identification of the Gia Lai specimen, Kuznetsov
and Borissenko13 and Meijaard etal.16 called for follow-up surveys
to assess the distribution and conservation status of silver-backed
chevrotain. In their 2004 publication describing the Gia Lai sil-
ver-backed chevrotain, Kuznetsov and Borissenko noted that,
by the mid-1990s, the area around Dak Rong and Buon Luoi had
undergone severe deforestation13. The authors also suggested that,
over the course of the 1978 to 1993 surveys, hunting pressure had
already resulted in chevrotain declines13. Despite these warnings,
no follow-up search efforts appear to have taken place, and there
were no confirmed records of the species for more than 25 years.
Given the considerable increase in hunting pressure that has
occurred in Vietnam since the early 1990s17, it was unclear whether
the species still existed. Once again, the silver-backed chevrotain
became a lost species.
We conducted targeted surveys to search for the silver-backed
chevrotain. First, we used interview surveys to obtain information
on the occurrence of potential silver-backed chevrotains in the
vicinity of Nha Trang, then conducted follow-up camera-trapping
in the most promising area. Interviews were conducted in three
Vietnamese provinces and covered four forest blocks, only one of
Camera-trap evidence that the silver-backed
chevrotain Tragulus versicolor remains in the
wild in Vietnam
An Nguyen1,2,8, Van Bang Tran 3, Duc Minh Hoang 3, Thi Anh Minh Nguyen3, Dinh Thang Nguyen4,
Van Tiep Tran4, Barney Long1, Erik Meijaard 5,6, Jeff Holland7, Andreas Wilting 2 and
Andrew Tilker 1,2,8*
NATURE ECOLOGY & EVOLUTION | VOL 3 | DECEMBER 2019 | 1650–1654 | www.nature.com/natecolevol
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