Lion-Tailed Macaque, Macaca silenus
Geographic Distribution and Habitat
Primarily arboreal, the beautiful lion-tailed macaque, also known as the wanderoo, thrives in the upper canopy of tropical evergreen rainforests and monsoon forests, at a wide range of elevations, from 330 to 6,000 ft (100–1,850 m).
They are endemic to the Western Ghats, a massive north-south running mountain range in India that spans 990 mi (1,600 km) and is only interrupted by the Palghat gap, which is 25 mi (40 km) wide. It crosses the states of Kanataka, Kamil Nadu, and Kerala on the southwestern coast of the Indian peninsula. Also known under its original name of Sahyadri, or Benevolent Mountains, this area is one of the world’s richest for its biological diversity.
Size, Weight, and Lifespan
Lion-tailed macaques are rather small compared to other macaques. They are about 15–24 in (40–60 cm) tall. Males weigh up to 33 lb (15 kg), twice as much as the smaller females. Their tail is 9–15 in (24–38 cm) long and helps them keep their balance while in the canopy. They can live up to 20 years in the wild and nearly forty in captivity.
In India, lion-tailed macaques are referred to as singalika or “lion-like.” Indeed, they have majestic silvery-white manes that contrast sharply with the silky black fur of their bodies and their hairless black faces. Their tails end in pointy tufts of hair similar to that of lions. This feature is more prominent in males than females.
The males have impressive long and sharp canines that they show off to discourage other males from challenging them. Their tongue is 3.5 in (9 cm) long. They have a long snout with large nostrils. Their eyes are a beautiful hazelnut shade and highlighted by delicately drawn black eyelids. Infants are born with lighter faces and their manes do not grow until they are about 2 months old.
Like all other macaques, lion-tailed macaques have cheek pouches which can store the same amount of food as their stomach—a handy feature to carry extra food while foraging. They are quadrupedal, meaning they walk on all four limbs. The opposable digits on their hands and feet make it easy for them to perform all kinds of activities including climbing, grooming, and feeding. They have black fingernails and the back of their hands and feet have ridges, just like ours do.
Lion-tailed macaques are selective eaters that live in mature mountainous rainforests, where food resources can be limited and widely scattered. Their main staple is fruit—mostly from trees in the fig family. When fruit is less abundant, they supplement their diet with a variety of delicacies that include seeds, sap, cones, shoots, pith, flowers, insects, snails, birds eggs, tree frogs, and small animals like lizards, bats, and Indian giant squirrel babies.
Their environment is rapidly changing due to human encroachment, wildfires, land conversion for crop plantation, and other human activities. In some areas, the landscape is drastically different from what it was a few years ago. Many tall trees have been cut or burnt to make room for crops and a wide variety of non-native plants have been introduced. The decreasing populations of lion-tailed macaques have had to adapt and they have been observed altering their diet in unpredictable ways, like feeding on non-native flowering maesa plants or even coffee plants. Because the fruits they normally eat are less available (especially between September and November), they are consuming more insects and spend a lot more time foraging on the ground than they used to.
Behavior and Lifestyle
Lion-tailed macaques spend half the day foraging and the other half resting or traveling to find areas to forage. They spend little time engaging in social activities like grooming and playing. Males especially keep their distance from other males and engage less frequently in social interactions than males of some other primate species.
DNA sampling revealed that 2.11 million years ago, lion-tailed macaque troops living in the Palghat gap diverged into two distinct populations.
The Palghat gap was formed 500 millions years ago, long before mammals and birds populated the area.
A stamp featuring the lion-tailed macaque was released in the city of Puttur (India) on July 27, 2020.
Lion-tailed macaques are diurnal and live in groups of 10 to 20 individuals. There is typically one male overlooking several females and juveniles. There can sometimes be as many as 3 adult males to a group, but only one is dominant. Dominant males protect their troops from neighboring troops.
Females stay with the troop they are born into and gain status as they age. The higher-ranked females receive the most grooming but give very little grooming in return. Males, however, leave their troop once they reach maturity, at about 4–7 years old. During this transition period, while looking for a new home group, they join other males in bachelor troops. Competition is high at that stage of their lives. A young male may strategically target an older or injured alpha male and challenge him to take over as leader of the troop. Males often migrate to many different groups until they are able to attain the top-ranking status.
Lion-tailed macaques are very intelligent and resourceful—for instance, in the wild, they use leaves to remove poisonous stingers from chrysalises before eating them. They also use forest litter as a sponge to extract water from tree holes. In captivity, a group of lion-tailed macaques invented tools to extract syrup from a container left at their disposal. At another site, lion-tailed macaques spontaneously used coconut shells to drink from a pool of water.
Lion-tailed macaques use at least 17 different vocal patterns, as well as body language, to communicate. Alarm calls are used to signal the presence of a predator, like the crested serpent eagle. Territorial boundary calls are uttered by dominant males and directed at neighboring troops to keep them at bay. Loud calls with bared teeth are strategic displays of strength that are usually sufficient to prevent a conflict—but when a challenger doesn’t back off, fights between males can lead to severe injuries, usually lacerations they inflict upon one another with their large canines. Mounting is used to intimidate a subordinate and as a show of strength. Branch-shaking is another way to show discontent and tell another monkey to beat it. Aggressive displays and loud calls are also used when the macaques and Indian giant squirrels are competing for the same food items. Lip-smacking is a friendly greeting, but a yawn with a grimace indicates dominance.
There is no specific breeding time, but most births coincide with the peak of the wet season when resources are abundant. While a female is in estrus, swelling occurs under her tail and she emits a courtship call to let males know that she is ready to mate. Even if there are several males in the group, only the dominant one is responsible for breeding. He examines her genitals before leading her away from the prying eyes.
Females have their first offspring at about 6 years of age. The mother usually gives birth to one baby, after a gestation period of 170 days (almost 6 months), and keeps that baby close, typically on her chest or back, until the infant is weaned at about 15 months. Once they have a baby, females do not have another one for at least 2.5 years.
Lion-tailed macaques are extremely important for seed dispersal. By transporting fruit in their cheek pouches and consuming them long distances from where they were gathered, they drop or defecate seeds far from the mother plant and contribute to the survival and propagation of many plant species in their environment.
The lion-tailed macaque is classified as Endangered by the International Union for Conservation of Nature (IUCN, 2015), appearing on the ICUN Red List of Threatened Species. There may be fewer than 2,500 mature individuals left in the world and the species is expected to further decline by over 20% in the next 25 years.
Natural predators, which include crested serpent eagles, mountain hawk-eagles, and dholes, are not the greatest dangers they face—habitat fragmentation is. As far back as the 1860s, with the establishment of tea plantations, the forest in the Western Ghats has been exploited for the globalization of agriculture. Since then, coffee plantations and timber harvest have created pockets of forest patches where the survival of the lion-tailed macaques is dire. On the Valparai Plateau, Anamalai Hills, for example, some macaque groups cannot find food and use dumps for sustenance. In recent years, lion-tailed macaques have been killed by cars because the highway to Valparai has been widened to ease traffic for locals and tourists. Because there are gaps in the canopy (and less than 40% mature trees), the monkeys have descend to the ground to cross between forest patches; some are killed by people, others are electrocuted attempting to use power lines as pathways. With their territory continuously shrinking, macaques are forced to leave the safety of the forest in order to eat. This increases human-primate conflicts, which are on the rise—especially in areas where lion-tailed macaques taught themselves how to remove roof tiles to enter houses and steal food.
Other threats include poaching for bushmeat and the exotic pet trade. Additionally, when wildlife and humans live in close proximity, there is always a danger for diseases to spread across species. In the case of lion-tailed macaques, scientists found elevated numbers of gastrointestinal parasites in groups living near humans and cattle. They see it as a direct consequence of habitat fragmentation and believe the presence of the parasites is a factor in the low birth rates and low juvenile survival in these groups.
Lion-tailed macaques are listed on Appendix I of the Convention on International Trade in Endangered Species (CITES). They are also protected by Schedule I, Part I, of the Indian Wildlife Protection Act of 1972, and several protected areas and national parks have been recognized throughout India as important areas to preserve. These include Kalakad-Mundanthurai in the state of Tamil Nadu, Silent Valley in the state of Kerala, and Brahmagiri-Makut in the state of Karnataka. However, management of the forest patches is difficult because many are on private lands where the forest department has no jurisdiction. Over the last twenty years especially, the lion-tailed macaque population has continued to decline and in some parts of the Western Ghats, the species seems to have disappeared.
Scientists discovered that lion-tailed macaques living in isolated forest patches have depleted mitochondrial DNA, which is passed from mother to offspring. Even though the male genetic material was not part of the study, these findings are significant—especially considering the fact that male dispersal doesn’t occur through non-canopy routes. Furthermore, in areas like the Valparai plateau in the Anamalai Hills, some of the forest patches have been isolated since the 1920s and lion-tailed macaques in the area form about 20% of the entire wild population with half of them living in those 20 forest patches, hence the urgent need to create forest corridors to allow for the free ranging of lion-tailed macaques, promote genetic diversity, and ensure these animals can reproduce and thrive. This can be achieved by planting native trees. Not only will these restore the canopy but they will also provide food for the monkeys. Another solution is to build wooden ladders, as was successfully done by the NGO Nature Conservation Foundation in Tamil Nadu State Forest.
Conservation agencies need to work closely with the local forest department, private land owners, municipalities, and local residents. Education will help shift the negative perceptions people may have of these animals. Teaching people not to feed the monkeys, preventing open waste disposal, ensuring regular garbage collection (including that of medical waste), and monkey-proofing houses are all actions that can be taken to lessen primate-human conflicts.
Finally, conservation efforts also include breeding in captivity. The first lion-tailed macaques were introduced to American zoos in the 19th century. As wild populations started to shrink, a breeding program was implemented in 1981 and the species was brought under the Species Survival Plan (SSP) of what is now known as the Association of Zoos and Aquariums (AZA). The goal was to establish a viable captive population. Europe joined the effort in 1989 and India in 1996. Unfortunately there has been little success of captive breeding in India to date.
- Pre-Historic and Recent Vicariance Events Shape Genetic Structure and Diversity in Endangered Lion-Tailed Macaque in the Western Ghats: Implications for Conservation (2015) – Muthuvarmadam S. Ram, Minal Marne, Ajay Gaur, Honnavalli N. Kumara, Mewa Singh, Ajith Kumar, Govindhaswamy Umapathy
- Journal of Threathed Taxa – 2009 – The Lion-tailed Macaque Macaca silenus (Primates: Cercopithecidae): conservation history and status of a flagship species of the tropical rainforests of the Western Ghats, India – Mewa Singh, Werner Kaumanns, Mridula Singh, H.S. Sushma & Sanjay Molur
- Current Science, Vol 112, no 10, 25 may 2017 – Interactions of lion-tailed macaques (Macaca silenus) with non-primates. In the Western Ghats, India – Joseph J Erinjery, Honnavalli N. Kumara, K. Mohan and Mewa Singh
- Behavioral Responses of Lion-Tailed Macaques (Macaca silenus) to a Changing Habitat in a Tropical Rain Forest Fragment in the Western Ghats, India – Mewa Singh, H. N. Kumara, M. Ananda Kumar, A. K. Sharma
- Journal of International Primatology – Male-Male Relationships in Lion-tailed Macaques (Macaca silenus) and Bonnet Macaques (Macaca radiate) – Mewa Singh, Tephillah Jeyara, U. Prashanth, Werner Kaumanns
- Primate Conservation 2018 (32) – 205-215 – Understanding Perceptions of People Toward Lion-Tailed Macaques in a Fragmented Landscape of the Anamalai Hills, Western Ghats, India – P. Jeganatham, Divya Mudappa, T. R. Shankar Raman and M. Ananda Kumar
- Time Budget and Activity Patterns of the Lion-Tailed Macaque (Macaca silenus) – G. U. Kurup and A. Kumar.
- Whose Habitat Is It Anyway? Role of Natural and Anthropogenic Habitats in Conservation of Charismatic Species – Mavatur Ananda Kumar, Sreedhar Vijayakrishnan and Mewa Singh
- Population Status of the Endangered Lion-Tailed Macaque (Macaca silenus) in Kaladad-Mundanthurai Tiger Reserve, Western Ghats, India – Hosur Subbarao Sushma, Rohini Mann, Honnavalli N. Kumara, Arumugam Udhayan – Primate Conservation 2014
- Center for Wildlife Studies cwsindia.org
- www.thehindu.com Different strategies needed to conserve lion-tailed, bonnet macaques, says study – Shubashree Desikan January 22, 2020
- Lion-tailed macaques (Macaca silenus) manufacture and use tools – Gregory C Westergaard
- Observations on tool use in captive lion-tailed macaque (Macaca silenus) – Shanthala Kumar, H. N. Kumara and Mewa Singh.
- Use of Enclosure Space by Captive Lion-Tailed Macaques (Macaca silenus) Housed in Indian Zoos – Avanti Mallapur, Natalie Waran, Anindya Sinha
- Human Presence Increases Parasitic Load in Endangered Lion-Tailed Macaques (Macaca silenus) in Its Fragmented Rainforest Habitats in Southern India – Shaik Hussain, Muthuvarmadam Subramanian Ram, Ajith Kumar, Sisinthy Shivaji, Govindhaswamy Umapathy.
Written by Sylvie Abrams, July 2020