TUFTED GRAY LANGUR

Semnopithecus priam

Geographic Distribution and Habitat
The tufted gray langur, Semnopithecus priam, also known as the Madras gray langur and the Coromandel sacred langur, is an Old World monkey found in east Asia on the mainland of southeastern India and the island of Sri Lanka. They are widely distributed throughout tropical dry and coastal forests. Their ability to adapt to human settlements allows them to live comfortably in areas with dense human populations such as villages, towns, residential areas, tourist areas, and temple grounds. Many tufted gray langur groups are found in archaeologically significant locations, like Polonnaruwa, Dambulla, Anuradhapura, and Sigiriya.

TAXONOMY IN TRANSITION

The tufted gray langur is one of many gray langur species. The exact number of species is debated and usually placed at 7 to 9. There is some debate that Semnopithecus priam thersites, the tufted gray langur subspecies that lives in Sri Lanka, for example, may actually be a separate species but, to date, there has not been sufficient evidence to designate them as such. 

Tufted gray langur range, IUCN 2020

Size, Weight, and Lifespan
Tufted gray langurs have an average body length of 24.1 in (61.1 cm) but can range from 21.7 to 31.5 in (55–80 cm) long. They have an average weight of 28.2 lbs (12.8 kg). This puts them in the mid-sized range for gray langurs; the average weight is 39 lbs (17.7 kg) for males and 34.8 lbs (15.8 kg) for females. Typically, gray langurs in the southern ranges are smaller than those in the north. Sexually dimorphic, females are smaller than males.

Females can live for over 30 years, whereas male lifespan is around just 18 years.

Appearance
Tufted gray langurs have a narrow tail that is longer than the rest of their body and is held high over their body. Their pelage is brownish to light gray and silky in appearance. Their heads are whitish and the hairs on the crown point upward in a distinct tuft that meets a central point, like a miniature mohawk hairstyle. Their faces are dark gray and they have thin ears that protrude from either side of their head. Their ventrum is a creamy yellow color and the hair around their feet is light-colored, though the digits are as dark gray as their face.

Photo credit: Charles J Sharp/Creative Common

What Does It Mean?

Agonistic:
Of, relating to, or being aggressive or defensive social interaction (such as fighting, fleeing, or submitting) between individuals usually of the same species.

Allogrooming:
Social grooming within a species.

Arboreal:
Physically adapted to living primarily or exclusively in trees.

Diurnal:
Active during daylight hours.

Folivorous:
Having a diet that consists of leaves.

Frugivorous:
Having a diet that consists of fruits.

Polygamous:  
Having more than one mate.​

​Sexually dimorphic:
When males and females have different characteristics (size, color, etc.) other than their reproductive organs.

Ventrum:
The stomach or belly area, the outside lower surface of the torso.

Visit the Glossary for more definitions

Diet
Tufted gray langurs are herbivores—primarily folivorous and frugivorous. Their diet consists mostly of leaves (52–61%), fruits (15–25%), flowers (4–13%), insects (0.4–3%) and other foods such as bark, gums, and soils (9–16%). More specifically, langur species eat a variety of food, including deciduous and evergreen leaves, leaf buds, herb leaves, coniferous needles, fruits, fruit buds, and evergreen petioles. They prefer mature leaves over young leaves.

In general, tufted gray langurs are not picky and will eat whatever food is available. They occasionally raid human crops and gardens or may be provided with handouts from humans like bananas and bread.

Behavior and Lifestyle
Tufted gray langurs are diurnal, arboreal, and semi-terrestrial. They primarily travel quadrupedally both on the ground and in the trees, and they prefer to run rather than walk. Other forms of locomotion include bipedal hops, climbing and descending with an upright body, and leaping.

They do not follow a consistent daily regimen, but for the most part, their daily life consists of feeding (25%), idle time (41%), traveling (15%), clinging (10%), and allogrooming (8%).

Tufted gray langurs are generally shy and only come to the ground when there is no visible danger. They doze in the highest branches of sleeping trees that are at least 39.4 feet (12 m) tall. In less natural areas, closer to human development, gray langurs have even been observed sleeping on top of telephone poles.

Daily Life and Group Dynamics 
Groups can be both polygamous and multi-male/multi-female. They range in size from 20 to 50 individuals. The larger groups can be led by a combination of males and females, but smaller groups are led by an alpha male. Home ranges of gray langurs in general vary from 0.03 to 8.5 mi² (0.07–22 km²). Groups do not usually move or alter their home range.

Groups are agonistic toward outsider groups and will display a variety of aggressive behaviors.

Fun Facts

The taxonomy of the gray langur is debated—until recently, all gray langurs were subsumed under one species, Semnopithecus entellus

Gray langurs are considered sacred in the Hindu religion.

Tufted gray langurs are one of several gray langur species named after characters from Homer’s ancient Greek epic set during the Trojan war, The Iliad. The scientific name for the tufted gray langur, S. priam, takes inspiration from Priam, the King of Troy. The other gray langurs named after characters in The Iliad are the Kashmir gray langur (S. ajax), named for the warrior Ajax the Greater, and the Taria gray langur, S. hector, named for Hector, the Prince of Troy.

Communication
Tufted gray langurs communicate the most with vocalizations that consist of barks, grunts, whoops, whistles, and howls.

Vocalizations are used for a variety of reasons including warning calls, like a harsh bark for nearby predators, and grunt barks for other rival groups. Many members of a group will “hiccup” when another group is sighted. Aggressive interactions between males are signified by barks, rumble screams, and grunts.

Reproduction and Family
There is very little known about tufted gray langur reproduction, but in general gestation lasts six months and females give birth to a single infant. Mothers care for their offspring for at least three months after birth.

Gray langur females do not show obvious signs of pregnancy and will continue to mate with males throughout their pregnancy, which can help trick males and prevent infanticide. New males will commit infanticide when they take over a group in order to replace the infants with their own offspring. In rare cases, females will abort their own offspring due to the stress of a new male takeover.

Gray langurs can be reproductively active late into their 20s in captivity.

Ecological Role
Due to their diet, tufted gray langurs are seed dispersers of a variety of fruits. Additionally, other animals, like cattle or deer, can benefit from food items that are dropped or dislodged during tufted gray langur foraging.

Conservation Status and Threats
The International Union for Conservation of Nature lists the tufted gray langur as Near Threatened (IUCN, 2015). Their population trend is listed as decreasing, though their global population size in unknown. The steady decline of their habitat in Andhra Pradesh, India, suggests a larger declining population trend. In the past thirty years, the habitat in Sri Lanka has shrunk by 50%.

Threats include:

  • Hunting (a major threat), rampant in the eastern Ghats and forests of the eastern coast, where habitats are vulnerable and unprotected
  • Habitat destruction and loss (also major threats), through residential and commercial development and agriculture
  • The pet and bushmeat trades
  • Predation by leopards, dholes, tigers, and wolves

Gray langurs are regarded as sacred by Hindus and are generally treated respectfully and left unbothered, but excessive ransacking of farms and homes by the gray langurs’ can lead to retaliation and persecution from humans. In heavily trafficked areas, gray langurs also fall victim to vehicle collisions.

Conservation Efforts
Tufted gray langurs are listed in Appendix I of the Convention of International Trade in Endangered Species (CITES), but the laws prohibiting the killing and/or capturing of gray langurs are difficult to uphold and are rarely locally enforced.

They are also listed in the Schedules II, Part I of the Indian Wildlife Protection Act (1978) amended up to 2002, and in Sri Lanka they are included under the Fauna and Flora Protection Act number 2.

Tufted gray langurs exist in many protected areas throughout their range. In India, they occur in many national parks, like Sri Venkateshwara and Bandipur, and a slew of sanctuaries and temples, like Nellapattu Sanctuary, Biligiri Rangsweamy Temple, Chinnar Sanctuary, and Mundanthurai Sanctuary. In Sri Lanka, they can be found in the Knuckle Range Forest Reserve, Ampara Sanctuary, Buggargala Sanctuary, Kanthale Naval Sanctuary, Wilpattu National Park, Giritale National Park, Bundala National Park, and Madura Oya National Park.

In order to better protect this species, more research needs to be conducted on taxonomy, human-animal conflict, effective habitat management, and public education.

​References:

  • http://animalia.bio/tufted-gray-langur
  • https://www.iucnredlist.org/species/135440/4128558#threats
  • http://pin.primate.wisc.edu/factsheets/entry/gray_langur/taxon
  • https://www.monkeyland.co.za/gray-langurs-or-hanuman-langurs_article_op_view_id_1964

Written by Rachel Heim, September 2019