First described in 1863 from a pair of antlers, Schomburgk's deer received little scientific attention until it was nearly extinct. Despite numerous European expeditions to locate this species in the early 1900's, the scientific literature has few details to offer, save for a running account of the putative range areas that were searched but from which the deer was already locally extinct. Only second-hand anecdotes of the species' habits in the wild were ever recorded; the species died out in the wild around 1932 and the last known captive animal was killed in 1938. All of the photographs of living animals depict a single male that lived at the Berlin Zoological Gardens from July 29, 1899 to September 7, 1911. Only one full mounted specimen is known to exist, in the Muséum National d'Histoire Naturelle of Paris, France.

Head and body length: Unrecorded; presumably like barasingha (Rucervus duvaucelii)

Shoulder height: 104 cm

Tail length: 10 cm

Adult weight: Unrecorded; presumably similar to barasingha (Rucervus duvaucelii)

Very limited information exists on the physical characteristics of R. schomburgki, and all descriptions refer solely to adult males. In general appearance, this species closely resembled the barasingha (Rucervus duvaucelii); indeed, at the time of its description, many people believed it to be a regional form of this species, and several captive individuals had been identified simply as barasingha from Thailand.

The pelage was thick and coarse-looking, due to the hairs being of different lengths; a mane of longer hairs (~5 cm in length) created a fringe above the forelegs. The overall coloration was a uniform brown. In summer, the overall color was golden reddish-brown with a distinct dark brown middorsal line that extended onto the upper surface of the tail. In winter, the coloration was darker, and the coat shaggier. The underparts - including belly, inner thighs, underside of tail, underside of muzzle, and throat - were whitish. The hooves were large and could be spread widely. Large eyes, a tapered muzzle, and large ears (16.5 cm long and 9.7 cm wide) characterized the face. The forehead was darker and slightly more rufous than the body, while the cheeks were paler and grayish. The lower lip was white, and a dark brown stripe ran from the rhinarium to the upper lip as in the barasingha.

Male Schomburgk's deer were remarkable for their antlers, which were exceptionally large and complex. Although there is a high variability in the known antler specimens, they all show a characteristic dichotomous branching pattern, in which every fork results in two relatively equal branches. With a short main beam and multiple forks, the antlers appeared "basket-like" - good sets of antlers regularly had 16-20 tines, with up to 33 tines recorded (by comparison, the related barasingha typically has 12 tines on a mature set of antlers).

Similar species

• In appearance, Schomburgk's deer was similar to the barasingha (Rucervus duvaucelii), although it was easily distinguished by range and by the basket-like antlers of males.
• Female Schomburgk's deer were suggested to resemble Eld's deer (Rucervus eldii), in that local reports distinguished between males of the two species, but not the females.

Although a few Schomburgk's deer were housed in European zoos and even bred, their reproductive habits were never recorded. Most aspects of the species' life history likely resembled that of the barasingha (Rucervus duvaucelii). The antlers of a male that lived at the Berlin Zoo were dropped in February, suggesting that the natural breeding season was likely near the end of the year.

Very little known; even its habitat of open, swampy country is inferred rather than well-documented. The large, complex antlers of males would not have been conducive to an existence in dense forest. Anecdotal reports suggest that Schomburgk's deer congregated on high ground and on floating grass islands during the high water season, from where they were easily hunted. The last individuals observed in the wild were seen with Eld's deer herds. The vocalizations of a male at the Berlin Zoo were described as a short, high bleat.

Family group: Believed to be herds of females and young, attended by a single adult male.

Diet: Presumably grasses, reeds, and other swamp vegetation.

Main Predators: Presumably tiger and leopard.

Believed to be native to the open, swampy floodplains and river valleys of central Thailand. However, the regular trade in the spectacular antlers created numerous reports of occurence elsewhere. The approximate range is depicted in the map below.

IUCN Red List: Extinct (2015).

CITES Listing: Not listed (2018).

Threats: Pushed to extinction by habitat loss and hunting.

When first described in 1863, Schomburgk's deer was reported as "fairly plentiful" in central Thailand. However, railway expansion north from Bangkok (leading to increased human presence, including hunting) and the conversion of wetland habitat to rice fields (notably between 1892 and 1906) caused a rapid decline in the population numbers. By 1918, Schomburgk's deer was reported to be on the verge of extinction, and in 1924, the flow of antlers from the north into Bangkok trading centres had dramatically slowed. The last records of wild Schomburgk's deer were in 1932 near Sai Yoke and Kwae Yai; the last known captive individual died in 1938.