Gray Snub-Nosed Monkey, Rhinopithecus brelichi
GRAY SNUB-NOSED MONKEY
Rhinopithecus brelichi
Geographic Distribution and Habitat
The gray snub-nosed monkey is found in the Fanjingshan Nature Reserve in the Wuling Mountains in south-central China. There is also evidence that the species may be present in nearby forests. They live in mixed deciduous and evergreen mountain forests with heavy rainfall (79 in, or 200 cm, per year) and snowfall in the winter. They live at high altitudes (potentially over a mile high, or 1.6 km) in the summer and move to lower altitudes in the winter to avoid snow.
This monkey is primarily found in China’s Ghizhou province, which lends the species its other name, the Ghizhou snub-nosed monkey.
Size, Weight, and Lifespan
Gray snub-nosed monkeys are larger than most of their relatives. They stand at 25-29 in (64-73 cm) tall with a tail length of up to 38 in (97 cm). Males are almost twice as heavy as females, weighing in at about 33 lb (15 kg) on average compared to the average female weight of 17.6 lb (8 kg).
There is no recorded lifespan for this monkey, but one of their closest relatives, the golden snub-nosed monkey, can live to be over 23 years old in captivity.
Appearance
Gray snub-nosed monkeys can be immediately recognized by their pale blue face, full lips, large black eyes, and their namesake—a flat, upward-facing nose with large nostrils. Their fur is generally an uneven mix of gray, black, red, and brown. In addition to being bigger, males are also more brightly colored and have greater contrast than females. Males also have white nipples and genitals. Gray snub-nosed monkeys have a distinct white patch of fur on the nape of their neck.
Diet
Half of the gray snub-nosed monkey’s diet is made up of leaves with an even split between mature leaves and young leaves, although they prefer young leaves since they are less toxic. Another quarter of their diet is made up of fruits and seeds. The remaining portion of their diet consists of buds, flowers, and insect larvae. Diets change with the seasons. In the winter, the gray snub-nosed monkey is heavily dependent on the buds of Sprenger’s magnolia. In the spring, leaves make up around 93% of their diet. Like all leaf monkeys, snub-nosed monkeys have multi-chambered stomachs to aid in the digestion of plants.
Behavior and Lifestyle
Gray snub-nosed monkeys are diurnal (active during daylight hours) and spend most of their lives in the trees, although they are not averse to traveling on the ground.
The gray snub-nosed monkey was first described in 1903 and was thought to be extinct until the skull of one was found in 1962. The first living specimen was found by researchers in 1967.
Gray snub-nosed monkeys live in groups of up to 10 individuals, which include a dominant male, a harem of females, and their offspring. These groups may combine with others to form temporary associations of up to 400 monkeys, which is over half the total population of the species.
Although groups can often be antagonistic toward each other on normal days, they become much friendlier when forming these supergroups. The babies in one group have been seen playing with babies from other groups with a single male watching over the group.
All-male groups consisting of 2 to 5 individuals usually live near family groups, waiting for an opportunity to take over a harem.
There is no significant research related to the communication of the gray snub-nosed monkey, likely due to its rarity and remote location. Their closest relative whose communications are well studied is the golden snub-nosed monkey, who lives to the northwest of the gray snub-nosed monkey and separated from them around 2.42 million years ago. Even by evolution standards, two and a half million years can be a long time, and two scions of the same ancestor can differentiate quite a bit. However, we can make some safe assumptions regarding the gray snub-nosed monkey thanks to their golden cousin.
Due to their large nostrils, golden snub-nosed monkeys can vocalize ventriloquially, meaning they can vocalize without moving their mouth. Since gray snub-nosed monkeys have similar nostrils, they may be able to communicate the same way. Golden snub-nosed monkeys have a rich repertoire of vocalizations, numbering at least 18 individuals calls, which can be linked to the fact that they often gather in groups of several hundred monkeys. In such large groups, calls must be separate and distinct from one another to be understood by other members. Since gray snub-nosed monkeys also gather into similar-sized groups, they likely have a similar range of vocalizations.
Of course, the only complete conclusion one can make here is that more research is needed on the gray snub-nosed monkey.
Mating in the wild occurs from September to October. Females avoid competition by staggering their mating periods, meaning that if one female in a group mates in early September, the other will hold off on mating for another week or so. Since groups are often in close proximity to other groups, mating outside of their group may occur, though it is rare. Babies are born between March and May. Females tend to give birth every two to three years.
Babies are carried around by their mothers in the first month of life. After that, they gradually grow more independent before being weaned off their mother’s milk between 12 and 20 months of age. All of the females in the group help raise the babies. Fathers may occasionally play with their offspring, but they do not take on much of a role in parenting outside of protection.
Males and females reach puberty after about 3 years, at which point the males will leave their natal group while females will usually stay. Although they have reached maturity, both males and females often wait at least two years before mating. It is unknown why males delay their mating opportunities, but for females, as is the case in most mammals, it is usually unhealthy to get pregnant immediately following puberty and it is best to wait until the rest of their body has fully matured.
With seeds and seed-bearing fruits making up 20–30% of their diet, gray snub-nosed monkeys are critical seed dispersers in their small habitat. Seeds that survive digestion are defecated far away from their parent tree. This creates a more diverse, and thus healthier, habitat, which benefits local plants, animals, and even humans.
Gray snub-nosed monkeys are listed as Critically Endangered by the International Union for Conservation of Nature (IUCN, 2022), appearing on the IUCN’s Red List of Threatened Species, due to their decreasing population and the continued degradation of the quality of their habitats due to human activities.
They reside in an area that is smaller than 38.5 square miles (100 km²) in just one location, the Fanjingshan National Nature Reserve. Within the area mentioned, their total area of occupancy is estimated to be only 10.5 square miles (27–28 km²). The construction of a tram within the park has further reduced the gray snub-nosed monkey’s area of occupancy. Habitat quality continues to decline due to ongoing disturbances by tourism.
In 2020, it was estimated that the number of mature individuals had declined by about 10% in just four years. The remaining population is small, with no more than 650 individuals being estimate. However, that may be an overestimation with the actual number closer to 400 individuals remaining in the wild. Mature individuals, with stronger survival rates than youngsters and, of course, breeding capabilities, are only a portion of this total.
A more recent study based on direct field observations to calculate the population density of gray snub-nosed monkeys in the reserve found that the remaining population totals only between 125–336 individuals (with mature individuals making only a portion of this total), and this appears to represent a single multilevel society. All individuals occur in a single subpopulation. Since the Fanjingshan National Nature Reserve is foggy for most of the year and the terrain is steep, it is extremely difficult to accurately investigate and assess population size.
The existing small population is vulnerable to inbreeding and has a limited distribution. This has resulted in low genetic variability to adapt to environmental and climate change. The Fajingshan National Nature Reserve maintains a captive colony with five individuals in Beijing Zoo. Captive breeding programs have been slow.
Since the 1990s, the main threat to gray snub-nosed monkeys is continued habitat disturbance, including both tourism and infrastructure. Tourism is a growing threat, with roads and other modes of transport, such as cable cars, constructed to cater to the tourist needs.
Historically, the primary threats to the species included occasional illegal hunting for meat and use in traditional medicine, capture in snares intended for other animals, and habitat disturbance. Since the small population is vulnerable to inbreeding and has a limited distribution, this could mean low genetic variability to adapt to environmental and climate change. Since they only occur in one location, they are especially vulnerable to disease outbreaks and natural catastrophes.
Per the IUCN’s 2022 assessment, this species is included in CITES Appendix I. It is also listed as a Category I species under the Chinese Wildlife Protection Act of 1989. The publication of the latest population sizes and group numbers by the reserve or the authorities is an urgent conservation priority.
This species is assessed as Critically Endangered on the Red List of China’s Vertebrates.
The Fanjingshan Nature Reserve holds a captive breeding colony to help build a healthy population. There have also been discussions of relocating some monkeys to neighboring reserves so the species can become more diverse and less susceptible to disease, catastrophes, and other possible threats.
Many thanks to Cyril C. Grueter, PhD for providing and allowing us to use his stunning photos of the gray snub-nosed monkey.
To learn more about Dr. Grueter and his work, visit www.cyrilgrueter.net.
- Kolleck, Jakob, et al. “Genetic Diversity in Endangered Guizhou Snub-Nosed Monkeys (Rhinopithecus Brelichi): Contrasting Results from Microsatellite and Mitochondrial DNA Data.” PLoS ONE, vol. 8, no. 8, 29 Aug. 2013.
- Xiang, Zuo-Fu, et al. “Current Status and Conservation of the Gray Snub-Nosed Monkey Rhinopithecus Brelichi (Colobinae) in Guizhou, China.” Biological Conservation, vol. 142, no. 3, 2009, pp. 469–476.
- Xiang, Zuo-Fu, et al. “Diet and Feeding Behavior of Rhinopithecus Brelichi at Yangaoping, Guizhou.” American Journal of Primatology, vol. 74, no. 6, 2012, pp. 551–560.
- https://www.arkive.org/grey-snub-nosed-monkey/rhinopithecus-brelichi/
- http://www.iucnredlist.org/details/19595/0
- http://www.iucnredlist.org/details/194009/0
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- http://pin.primate.wisc.edu/factsheets/entry/golden_snub-nosed_monkey/taxon
Written by Eric Starr, August 2018. Conservation Status and Threats and Conservation Efforts updated October 2022.