Dung, Giao, Chinh, Tuoc, Arctander, MacKinnon, 1993
The Saola, Vu Quang ox, spindlehorn, or Asian bicorn, also, infrequently, Vu Quang bovid (Pseudoryx nghetinhensis), is one of the world's rarest large mammals, a forest-dwelling bovine found only in the Annamite Range of Vietnam and Laos. Related to cattle, goats, and antelopes, the species was defined following a discovery of remains in 1992 in Vũ Quang Nature Reserve by a joint survey of the Ministry of Forestry and the World Wide Fund for Nature. Saolas have since been kept in captivity multiple times, although only for short periods. A living saola in the wild was first photographed in 1999 by a camera trap set by WWF and the Vietnamese government’s Forest Protection Department (SFNC).
An adult saola stands at about 80–90 centimetres (31–35 in) at the shoulder, with its entire body length measuring around 150 centimetres (59 in) (the tail measures an additional 25 centimetres (9.8 in)) and weighs 90–100 kilograms (200–220 lb). Its hair is straight, short, and unusually soft for an animal partly adapted to a montane habitat, and is usually of a medium chocolate brown color (though some have been noted to contain variations of a reddish tone). Neck and belly are of a slightly paler shade, as well as various white markings scattered across its body, such as white patches on the feet, vertical stripes across the cheeks, and splotches on the nose and chin. A black dorsal strip extends from between the shoulders down and back to fade out into the top of the tail. The tail is tricolored, splitting evenly into three horizontal bands of medium brown, cream, and black, with the cream blending into the white band that extends across its rear.
Saolas of both sexes possess a pair of slightly diverging horns that resemble the parallel wooden posts locally used to support a spinning wheel (thus the familiar name "spindlehorn"). These are generally dark-brown or black and about 35–50 cm long; twice the length of their head. There appear to be no significant differences between the horns of males and females. The saola has round pupils with dark-brown irises and a cluster of white whiskers about 2 cm long with a presumably tactile function that protrude from the end of the chin. Its tongue can extend up to about 16 cm, with its upper surface covered in fine, backward-pointing barbs. Saola skin is 1–2 mm thick over most of the body, but thickens to 5 mm near the nape of the neck and at the upper shoulders. This adaptation is thought to protect against both predators and rivals' horns during fights.
The saola possesses a pair of highly developed maxillary glands on either side of its snout, used in marking territory. Glands consist of rectangular shallow depressions of about 1.5 cm deep along the upper muzzle, covered by a muscular flap that can be raised about 3 cm to expose the gland. Scent glands are rubbed against the underside of vegetation, leaving a musky, pungent paste. The saola's scent glands are thought to be the largest of any living mammal.
Taxonomy and evolution
The saola, Pseudoryx nghetinhensis (Dung, Giao,Chinh, Tuoc, Arctander and MacKinnon, 1993), belongs to the family Bovidae, placing it with cattle and antelopes. The discovery of saola remains in 1992 generated huge scientific interest due to the animal's special physical traits. The saola differs significantly from all other bovid genera in appearance and morphology, enough to place it in its own genus (Pseudoryx).
A recent sequencing study of ribosomal mitochondrial DNA of a large taxon sample divides the bovid family into two major subfamilial clades. The first clade is the subfamily Bovinae consisting of three tribes: Bovini (cattle and buffaloes), "Tragelaphini" (Strepsicerotini) (African spiral-horned bovids) and "Bosalaphini". The second clade is the subfamily Antelopinae which includes all other bovids. Antelopinae is composed of the three tribes, Caprini (goats and muskox), Hippotragini (horse-like antelopes), and Antilopini (gazelles).
Since its physical traits are so complex to classify, Pseudoryx had been classified variously as member of the Caprinae subfamily and as belonging to any of the three tribes of the Bovinae subfamily: Boselaphini, Bovini and Tragelaphini. Recent DNA analysis has led scientists to place the saola as a member of the tribe Bovini. The morphology of its horns, teeth and some other features indicate it should be grouped with less-derived or more ancestral bovids. Scientific consensus may lead to classifying the saola as the sole member of a proposed new tribe Pseudorygini.
Habitat and Distribution
Saola inhabit wet evergreen or deciduous forests in eastern Indochina, preferring rivers and valleys. Sightings have been reported from steep river valleys at 300–1800 m above sea level. In Vietnam and Laos, their range appears to cover approximately 5000 km2, including four nature reserves. During the winters, Saola tend to migrate down to the lowlands.
Behavior and reproduction
Saolas appear to be mostly solitary, although they have been reported in groups of two or three as well as up to six or seven. Saola grouping patterns resemble other dense vegetation species, such as the bushbuck, anoa, and sitatunga. When they sleep, they have their fore legs tucked under their bodies, necks extended, and the chin resting on the floor. Villagers reported that saolas are active in the mornings, afternoons, and nights.
Almost all available information on saola behaviour stems from observations of a single captive individual. Captured saola are calm in the presence of humans, allowing themselves to be petted and hand-fed, but display an intense fear of dogs. When they feel threatened, they adopt defensive positions which involve the snorting and thrusting of their heads forward, exposing their long, straight horns. Their ears are pointed up and straight back with arched backs and stiff postures. Occasionally, they secrete the paste from their maxillary glands as a defensive reaction. Saola vocalize with bleats.
Saolas urinate and defecate separately, dropping their hind legs and lowering the lower body, a common behaviour among bovid species. They spend a significant amount of time grooming themselves, making use of their strong tongues.
Very little information is available about their reproductive and pregnancy cycles. Only single-calf pregnancies have been documented so far. Calving occurs in the summer; the saola is likely a seasonal breeder, timing reproduction to coincide with the monsoon, at the very end of the dry season (between mid-April and late June). In the absence of more specific data, the gestation period has been estimated as similar to that of Tragelaphus species (about 33 weeks). Three reports of saola killings from nearby villagers involved young accompanying mothers. One possessed 9.5 cm long horns, another an estimated 15 cm, and the third 18.8 cm; these varying horn lengths suggest a birth season extending over at least 2–3 months.
Saola are browsers, as suggested by their relatively undeveloped incisors, and have been reported eating small leafy plants—especially fig leaves and stems—along rivers. While little is known about the full range of their diet, saolas in captivity have subsisted on a diet of leafy plants such as a Asplenium fern species (also known as spleenwort), broad dark-green plants of the Homalomena genus, and various species of broad-leaved shrubs or trees of the Sterculiaceae family. They appear to feed predominantly during daylight and twilight hours.
The saola is currently considered to be critically endangered. Its restrictive habitat requirements and aversion to human proximity are likely to endanger it through habitat loss and habitat fragmentation. Saola suffer losses through hunting for local trophy hunting and the illegal trade in furs, traditional medicines, and for use of the meat in restaurants and food markets. They also sometimes get caught in snares that have been set to catch animals raiding crops, such as wild boar, sambar, and muntjac. More than 26,651 snares have so far been removed from Saola habitats by conservation groups.
The key feature of the area occupied by the saola is its remoteness from human disturbance. Saola are shot for their meat, but hunters also gain high esteem in the village for the production of a carcass. Due to the scarcity, the locals place much more value on the saola than more common species. Because the people in this area are traditional hunters, their attitude about killing the saola is hard to change; this makes conservation difficult. The intense interest from the scientific community has actually motivated hunters to capture live specimens. Commercial logging has been stopped in the nature reserve area of Bu Huong, and there is an official ban on forest clearance within the boundaries of the reserve.
Species of conservation concern are frequently hard to study; there are often delays in implementing or identifying necessary conservation needs due to lack of data. Because the species is so rare, there is a continuous lack of adequate data; this is one of the major problems facing saola conservation. Trained scientists have never observed saola in the wild. Unfortunately, because it is unlikely that intact saola populations exist, field surveys to discover these populations are not a conservation priority.
The Saola Working Group was formed by the IUCN Species Survival Commission's Asian Wild Cattle Specialist Group, in 2006 to protect the saolas and their habitat. This coalition includes about 40 experts from the forestry departments of Laos and Vietnam, Vietnam's Institute of Ecology and Biological Resources, Vinh University, biologists and conservationists from Wildlife Conservation Society, and the World Wide Fund for Nature.
A group of scientists from the Vietnam Academy of Science and Technology in central Hanoi, within the Institute of Biotechnology, investigated a last resort effort of conserving the species by cloning, an extremely difficult approach even in the case of well-understood species. However, the lack of huemul female donors, receptive females and the interspecific barriers greatly compromise the success of cloning technique.
The name saola has been translated as "spindle[-horned]" although the precise meaning is actually "spinning-wheel post horn". The name comes from a Tai language of Vietnam, but the meaning is the same in the Lao language. The specific name nghetinhensis refers to the two Vietnamese provinces of Nghệ An and Hà Tĩnh while Pseudoryx acknowledges the animal's similarities with the Arabian or African oryx. Hmong people in Laos refer to the animal as saht-supahp, a term derived from Lao meaning "the polite animal", because it moves quietly through the forest. Other names used by minority groups in the Saola's range are lagiang (Van Kieu), a ngao (Ta Oi) and xoong xor (Katu)  In the press, saolas have been referred to as "Asian unicorns", an appellation is apparently due to the saola's rarity and reported gentle nature, and perhaps because both the saola and the oryx have been linked with the unicorn. No known link exists with the Western unicorn myth or the "Chinese unicorn", the qilin.
Other rarely seen large mammals of the Indochina peninsula, also discovered in the 1990s:
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|Wikimedia Commons has media related to Pseudoryx nghetinhensis.|
- savethesaola.org, Saola Working Group Website
- BBC: Rare antelope-like mammal caught in Asia
- ARKive - images and movies of the saola (Pseudoryx nghetinhensis)
- Saola factsheet at Ultimate Ungulate
- "A new cow - a new species of ox, the pseudoryx, found in Southeast Asia - 1993 - The Year in Science", from Discover, Jan. 1994.
- The Vu Quang Bovid at BrainBox
- Vu Quang Ox - Pseudoryx nghetinhensis from the United Nations Environment Programme World Conservation Monitoring Centre
- Saola Conservation in Central Vietnam - Center for Biodiversity and Conservation, American Museum of Natural History