Vietnamese Mousedeer – Tragulus versicolor – Thomas, 1910

Science name: Tragulus versicolor – Thomas, 1910

Taxonomic:  Animalia>> Chordata>> Mammalia>> Artiodactyla >> Tragulidae >> versicolor

Species status: Endemic ; IUCN status: LC (Least Concern)

Description:

Physical Characteristics:
The Tragulus versicolor is a small, elusive ungulate, with head-to-body lengths ranging from 40-48 cm and weighing approximately 1.7 kg. Its most distinguishing feature is its two-toned coat: the hindquarters are silver-gray (giving it the common name “silver-backed”), while the head, neck, and shoulders are bright golden-brown. The tail is white underneath, with silvery tones transitioning to golden near the tip. The legs are yellowish-brown, and the rounded ears are grayish-brown. Males have elongated, tusk-like upper canines that protrude from their mouths, a common trait among chevrotains.

Body and Coat:
One of the most distinctive features of Tragulus versicolor is its two-toned coat. As its common name suggests, the hindquarters of the animal, starting from just behind the shoulders to the rump, are covered in silver-gray fur. This silvered area gives the animal a grizzled appearance, with the individual hairs having white tips, contributing to the “silver-backed” description. In contrast, the head, neck, and shoulders are a bright golden-brown color. This stark difference in coloration creates a visually striking appearance that helps distinguish the species from other chevrotains.

The nape of the neck has a darker wash of gray, and the hair in this region is particularly coarse and long, providing extra protection. The golden-colored throat is further marked by three thick white stripes that radiate outward from the pale underside of the jaw. One of these stripes continues uninterrupted down the midline of the chest, merging into the white belly. This distinctive stripe pattern is unique to the species and serves as a diagnostic feature.

Tail:
The tail of the Tragulus versicolor is short, measuring about 5 cm in length. It is white underneath, while the upper part is silvery, gradually transitioning to a golden tone near the tip. While the tail is not particularly long, it serves as a balance tool and, like many other small ungulates, may also be used in communication, such as signaling danger or other behaviors.

Legs and Hooves:
The legs of the silver-backed chevrotain are thin and delicate, yet strong enough to support the animal’s body in navigating through dense undergrowth and forested environments. The legs are covered in a yellowish-brown coat, blending with the forest floor and aiding in camouflage. The small hooves are well-adapted for silent movement, allowing the animal to move gracefully and almost undetected in its habitat.

Head and Face:
The head of Tragulus versicolor is small and rounded, with large, dark eyes that provide excellent vision in the dimly lit forest understory where it often resides. These expressive eyes are well-suited to detect potential predators. The ears are relatively large and pointed, providing a heightened sense of hearing to detect faint sounds of predators or other animals in the vicinity. The rounded ears are grayish-brown in color and lack any distinct facial markings, giving the face a soft, neutral appearance.

Mouth and Canine Teeth:
Males of the species possess elongated, tusk-like upper canine teeth, which protrude from the mouth. These canines are much more prominent in males than in females and are used for intraspecific combat, particularly during mating season when males may fight for access to females. Despite these tusks, the chevrotain has a small, delicate mouth adapted for browsing on soft vegetation.

Coloration and Camouflage:
The coloration of Tragulus versicolor is a key adaptation to its environment. The silver-gray fur on its back and its bright golden-brown sides and head provide an excellent camouflage in the dappled light of the forest floor. This coloration helps the chevrotain blend into its surroundings, making it difficult for predators to spot the animal, especially in dense vegetation. Additionally, the lighter undersides, including the white belly and under-tail, may help reduce the appearance of shadows while the animal moves, further aiding in its concealment.

Size Comparison:
Compared to other chevrotains, Tragulus versicolor is generally smaller. It is often compared to the lesser Malayan chevrotain (Tragulus kanchil), with which it shares overlapping habitats in parts of Vietnam. However, Tragulus versicolor tends to be smaller in size and is distinguished by its unique silver-backed coloration. In contrast, Tragulus kanchil typically has a more uniform reddish-brown coat and lacks the distinct silvery back and white belly stripe found in Tragulus versicolor.

Sexual Dimorphism:
There is little evidence of pronounced sexual dimorphism in Tragulus versicolor, aside from the more developed canines in males. Males use these canines during competition with other males, particularly during mating season. Females, on the other hand, tend to have shorter, less prominent canines, focusing their energy on nurturing their young rather than engaging in combat.

Comparison with Similar Species:
While Tragulus versicolor was once considered a subspecies of Tragulus napu (the greater Malayan chevrotain), it has since been recognized as a distinct species due to its unique physical characteristics, particularly its coloration. Its smaller size and distinctive two-toned appearance make it easier to distinguish from other chevrotains like Tragulus napu and Tragulus kanchil, although identification in the wild can still be challenging due to its elusive nature and similarities in body shape with other chevrotains.

Distribution and habitat:

Altitude:
The Tragulus versicolor inhabits elevations ranging from sea level to approximately 500 meters above sea level.

Range:
This species is native to Vietnam. The exact range remains uncertain, with known specimens collected near Nha Trang and in the Gia Lai Province. Its distribution is poorly understood, primarily due to its confusion with similar species, such as Tragulus kanchil. There have been very few confirmed sightings, and most specimens were obtained historically or in trade.

Habitat:
Tragulus versicolor inhabits a variety of forest types, including subtropical and tropical moist lowland forests, dry forests, and montane forests. It is also found in degraded and secondary forests, often in areas with dense undergrowth and proximity to water sources. Its habitat is characterized by forested areas ranging from deciduous to evergreen, and it has also been recorded in artificial landscapes like plantations.

Behaviour and ecology:

Social Structure:
Tragulus versicolor is solitary by nature but has occasionally been observed in pairs. It exhibits a halting gait when walking, and its small size and elusive behavior make it difficult to spot in the wild.

Feeding Habits:
The diet of Tragulus versicolor is not well-documented, but like other chevrotains, it is likely herbivorous, feeding on leaves, fruits, and other plant matter.

Reproduction:
Little is known about the reproductive habits of this species. However, based on other members of the Tragulus genus, it is presumed that the species gives birth to a single offspring after a gestation period of around 150 days. The fawn is likely to be precocial and hidden in dense undergrowth, with the mother returning to nurse and care for it periodically.

Conservation and status:

IUCN Red List Category and Criteria:
Tragulus versicolor is listed as Data Deficient due to the lack of comprehensive data on its population, distribution, and ecological requirements.

Population Trend:
The population trend is believed to be decreasing, but no accurate estimates of the number of mature individuals are available.

Threats:
The primary threats to Tragulus versicolor include habitat loss and degradation due to deforestation, agricultural expansion, and human activities. Hunting, especially with snares and guns, is also a likely threat, although specific data on this is lacking.

Conservation Actions:
The species is in urgent need of proper assessment to determine its population size, geographic distribution, and the specific threats it faces. While there are no targeted conservation measures specifically for Tragulus versicolor, recent rediscoveries near Nha Trang suggest that ongoing surveys and protective measures could be crucial for its survival.