10 Endangered species of Primate in Vietnam

Endangered Species (EN)

Endangered species, or species at risk of extinction, are facing a high risk of extinction outside of natural causes (according to the IUCN). They rank second on the IUCN Red List of threatened species. In 2016, Vietnam had 10 endangered species listed in this category.

Although the number of endangered species remains unchanged, 3 out of the 10 species have been elevated to the critically endangered level. Additionally, two species have been upgraded from vulnerable to endangered, and one species has been directly upgraded from least concern to endangered.

Information about 10 endangered Primate species in Vietnam

Germain’s Langur (Trachypithecus germaini)

The habitat of this endangered species extends from southern Myanmar through southern Thailand, southern Laos, Cambodia to southern Vietnam, specifically in the province of Kien Giang. The global population is not yet known, but it is steadily declining.

The silvered langur has black coloration on its hands, feet, and upper body, gradually transitioning to a lighter gray color on the lower part. They have a long gray tail and white fur on their round face. Juveniles of this species have bright orange fur.

The diet of silvered langurs consists of leaves, including foliage, shoots, and fruits. This diet requires resting periods, during which they may undergo regurgitation and rechewing. Trachypithecus germaini, like other Asian langurs, is a non-social primate species. They do not prioritize social behaviors over feeding and resting, which occupy most of their daily activities.

However, Trachypithecus germaini is often observed living in close-knit social groups ranging from 10 to 50 individuals. Predators of langurs, including silvered langurs, include clouded leopards, tigers, hunting dogs, and large snakes. Many small carnivores will prey on langur infants. Common threats to silvered langurs include hunting, trade in exotic pets, and habitat loss due to agricultural expansion.

Annamese Langur (Trachypithecus margarita)

The endangered silvered langur species used to have a widespread distribution in southern Central Vietnam, southern Laos, and eastern Cambodia along the western bank of the Mekong River. However, they are now only sporadically found in a few locations due to hunting, habitat loss, and in recent times, they have become extremely rare to spot in Vietnam.

The fur of this species is lighter in color compared to the fur of the Indochinese silvered langur. The current population of this species has not been estimated, but it is certain that their numbers are declining. Hunting for meat, medicinal use, and as pets is one of the threats to this species. The habit of consuming soil rich in sodium may be due to their consumption of toxic leaves, and the sodium helps them eliminate harmful substances (Jonathan C. Eames).

Indochinese Grey Langur (Trachypithecus crepusculus)

Previously, this species was classified as a subspecies of the Gray Langur. However, it was later separated, and this endangered species is found in China, Thailand, Laos, and Vietnam.

This is a small-bodied monkey species, weighing between 5 to 9 kg. They have distinctive features such as a fur coat ranging from ash gray to dark brown, a gray crest on the head, and blue and white skin around the eyes. The fur on the back is darker than on the belly. They have long hair on the sides, with silver highlights on the head. The tail is longer than the body, and the fur on the tail is very long. The limbs are long, with black hands, and the upper arms, legs, and tail have a silver-gray color.

Gray langurs live in mountainous forests in the northern and north-central provinces of Vietnam. They live in groups ranging from 3 to 30 individuals. They inhabit high tree forests on limestone mountains and do not live in bamboo mixed forests. They are diurnal and arboreal, spending their time climbing trees. They can be found foraging in the hillside areas near forests. They often sleep on vertical limestone cliffs or in dense tall tree canopies, sheltered from the wind. Gray langurs coexist with macaques and golden langurs without competing for food. Their diet primarily consists of fruits (24.4%), leaves (58.4%), and other plant materials (9.7%). Their natural predators include larger carnivorous animals.

Gray langurs breed throughout the year. Pregnant females have been observed in March and July. Females carrying infants on their chest have been observed in April, June, October, and December. They give birth to one offspring at a time, and newborns have a light yellow color.

Francois’s Langur (Trachypithecus francoisi)

It is the langur species with the northernmost distribution, ranging from southern central China to northern Vietnam. This langur species is currently facing an extremely serious threat.

They have thick, jet-black fur. Their cheeks are white, with wide white fur extending beyond the ear tufts. They typically have a black crest on their heads. The tail is longer than the body and is black in color. White-cheeked black langurs mainly live in forests on limestone mountains and forage in dense evergreen forests adjacent to their habitat. They live in groups. In the past, langur groups were often large, with 20 to 30 individuals (Le Hien Hao, 1973), but now they are more commonly found in groups of 5 to 15 individuals (Pham Nhat, 2000).

Their feeding activities occur in the morning and afternoon, with a break during midday. The peak feeding intensity of white-cheeked black langurs is observed in two periods: early morning until around 10 am and from 2 pm to 4:30 pm. The activity patterns vary throughout the day. During the hot season, langurs leave their sleeping places early, return to their caves late, and have a long midday rest. In the cold season, they start foraging later and return to their caves earlier. Francois’s Langur primarily feed on young leaves and forest fruits, and they do not consume animals.

Preliminary studies have documented 44 plant species from 22 families that serve as food sources for white-cheeked black langurs (Pham Nhat, 2000). They show a preference for certain plant species, including the Moraceae family, Euphorbiaceae family, and Arecaceae family. Research data indicates that although they consume a variety of fruits, the proportion of leaves, especially leaf stalks, is higher in their diet compared to fruits and stems. White-cheeked black langurs primarily sleep in caves.

During the hot season, they sleep on rocks or tree branches in front of the cave entrance, while during the cold season, they sleep inside the caves. The sleeping caves of langurs are often found in vertical rock walls. There is still limited data on the reproduction of white-cheeked black langurs. Field observations have shown that females carry infants at different months of the year, but the peak period is from March to July. They give birth to one offspring at a time, and newborns have yellow fur.

Hatinh Langur (Trachypithecus hatinhensis)

The Hatinh langur, an endangered species, inhabits a small area in central Vietnam, specifically limited to Quang Tri and Quang Binh provinces. Some individuals can also be found in Khammouane, adjacent to Laos.

They spend most of their time in the trees. They live in small groups of 7 to 8 individuals, consisting of one male along with females and their offspring. They are threatened by hunting, primarily for medicinal purposes. They are often captured near the entrances to their caves (Le Khac Quyet).

Northern Yellow-cheeked Crested Gibbon (Nomascus annamensis)

It was first described in 2010 based on howling and genetic data. This species is recorded in Central Vietnam, extending west to southern Laos and northeastern Cambodia. It has not been assessed by the IUCN yet but is considered endangered due to hunting, habitat loss, and its restricted range.

The Central Vietnam black-shanked douc langur is described as closely resembling the yellow-cheeked crested gibbon (Nomascus gabriellae). It is difficult to distinguish them from the yellow-cheeked crested gibbon. Females are differentiated by their facial features, with a darker crown and a darker patch on the chest (Tilo Nadler).

Males have black fur with less silver hair, and their black fur appears silver in sunlight. Their chest fur is brown, while the facial hair is golden and does not extend above the face, unlike other species within the same genus. Females have lighter fur, with a blend of orange and yellow, and fewer black marks on the head. The Central Vietnam black-shanked douc langur is distinct from other light-colored langur species in terms of the frequency and rhythm of their vocalizations for group calling and territorial defense against intruders.

Southern Yellow-cheeked Crested Gibbon (Nomascus gabriellae)

This langur species inhabits the southern region of Vietnam and the eastern region of Cambodia. It is closely related to the northern yellow-cheeked crested gibbon and can only be distinguished by their vocalizations. Deforestation, which leads to habitat loss, and the capture of young individuals for the pet trade are the main causes of population decline for this species.

Males and females in the Nomascus genus have two different colors. While males are black, which is characteristic of the genus, females are lighter in color (Nicolas Cornet). The agility of their muscles and bones allows them to easily cling to trees for movement.

This species is heavily hunted because their young are visually appealing and their calls are easily heard. As a result, the mothers of this species are often shot and the young are captured for the pet trade, which is one of the main reasons for the severe threat to this species.

Bengal Slow Loris (Nycticebus bengalensis)

They are found throughout Southeast Asia except for southern Vietnam. This species typically inhabits forests. They are often captured for the pet trade and used in traditional medicine. Their bites are venomous.

When they lick their forearm, the secretion from their forearm gland mixes with their saliva to form a toxic substance. Previously, this species was classified as “Vulnerable” (VU), indicating a high risk of vulnerability. However, it has since been reclassified as “Endangered” (EN), indicating a higher level of threat.

This slow-moving primate has large bulging eyes, small ears, and is mostly covered in dense fur. Its tail is short and stubby. It is a tree-dwelling species and forages during the day. Phylogenetic analysis shows that the large slow loris is most closely related to the Sunda slow loris.

However, some individuals in both species have DNA sequences that are similar to other species, indicating hybridization. It is the largest species in the Nycticebus genus, measuring 26-38 cm (10-15 inches) in length from head to tail and weighing 1-2.1 kg (2.2 to 4.6 lbs). The toxins it secretes from its brachial gland (a scent gland in its arm) differ chemically from other Nycticebus species and can be used to convey information about sex, age, health, and social status.

Traditional Asian medicine has used this species as a source of medicine, leading to their commercial exploitation. Countries like the UK have now banned the trade of this species and products derived from them. In Vietnam, the large slow loris is listed in the list of prohibited wildlife species for exploitation and use for commercial purposes.

Pygmy Slow Loris (Nycticebus pygmaeus)

They inhabit Cambodia, Laos, and Vietnam, with their range extending from the north to the south, except for the Mekong Delta. They can be found in all types of forests and are adaptable to degraded habitats. Despite being subject to strict conservation efforts, their population is declining significantly. Similar to their “cousin” the large slow loris, the small slow loris has been upgraded by the IUCN from “Vulnerable” to “Endangered,” indicating a higher level of threat.

Their diet consists of insects, beetles, fruits, young leaves, bird eggs, and young birds in nests. They inhabit various forest habitats, including bamboo forests and shrubby hills. As nocturnal animals, they curl up and sleep in tree canopies during the day. They primarily forage at night in open forests, on tree trunks, dense shrubs at the forest edge, and in agricultural fields.

They can move quickly through vegetation. They feed on fruits, small lizards, invertebrates, and especially tree gum. Females usually give birth to twins and carry their young for the first 2 to 3 weeks. The small and adorable slow loris has soft, reddish-brown fur with occasional patches of silver-white fur. There is a white stripe along the nose. The back has a dark reddish patch. The belly is silver-yellow. An adult Nycticebus pygmaeus measures only 19-23 cm in length and weighs between 377 and 450 grams.

The reproductive organs of the small slow loris are fully developed when females reach 16 months of age and males reach 18 months. The gestation period usually lasts from 184 to 200 days. When young, they cling to their mother’s belly. After six months, they are weaned. In Vietnam, the small slow loris is listed in the list of prohibited wildlife species for exploitation and use for commercial purposes.

Long-tailed Macaque (Macaca fascicularis)

This species is found in most of Southeast Asia and southern Vietnam. Although they are considered to be a species of low concern due to their wide distribution, on March 7, 2022, this species was upgraded from “Least Concern” to “Endangered,” making it the second most threatened category in the IUCN Red List.

The body length of adult individuals varies among subspecies, ranging from 38 to 55 cm, with relatively short arms and legs. Adult males are significantly larger than females, weighing 5 to 9 kg compared to the 3 to 6 kg weight of females. The tail is longer than the body, typically measuring 40 to 65 cm, and is used for balance when leaping distances of up to 5 m. The upper parts of the body are dark brown with lighter brownish-yellow patches. The underparts are light gray with a darker gray/brown tail.

There is fur on the crown that extends backward, sometimes forming a short crest in the middle. The skin on the feet and ears is black, while the skin on the nose is a light grayish-pink color. The eyelids often have distinct white patches, and there may be white spots on the ears. Adult males have prominent cheek flanges and beards on their cheeks, while females only have cheek beards. They have a cheek pouch used for storing food while foraging.

Conclusion

Here is the information about 10 endangered primate species in Vietnam that WANEE ASIA wants to provide to you. We hope that this will be useful information for you to learn more about these 10 primate species. Wishing you wonderful experiences in exploring the beautiful nature.

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