Lion-tailed Macaque: Endangered Primate of Western Ghats

The Lion-tailed Macaque (Macaca silenus) is an endangered primate found only in the Western Ghats of southwestern India. Characterised by a distinctive silvery-white mane around its face and a lion-like tail tuft, the species is one of the rarest macaques in the world. With only approximately 3,000-4,000 individuals remaining in the wild, it is classified as Endangered on the IUCN Red List. The species played a central role in the Silent Valley movement of the 1970s-80s — one of India’s most significant environmental conservation campaigns.

For UPSC, the Lion-tailed Macaque is a frequently tested topic in Environment & Ecology — covering endemism, conservation, IUCN status, and the Silent Valley controversy.

Basic Biology

Physical Characteristics

Other Names

• Wanderoo (old Portuguese name; still used occasionally)
• Singa (in some Indian languages)
• Sihgam (Kannada)

Distribution

Endemic to Western Ghats

The Lion-tailed Macaque is found only in the Western Ghats of India — specifically in:

Population

The species is fragmented across approximately 50 isolated populations, creating significant genetic challenges.

Habitat and Ecology

Preferred Habitat

• Tropical evergreen forests (shola forests)
• Altitude: 500-1,800 m
• Canopy dwellers — almost entirely arboreal
• Temperature range: 10-30°C (temperate to tropical)
• Rainfall: 2,000+ mm annually

Diet

Primarily frugivorous (fruit-eating):

• 60-80% of diet: Fruits (especially fig trees)
• Insects (10-20%)
• Leaves and buds (5-15%)
• Small vertebrates occasionally
• Not crop raiders — unlike Rhesus and Bonnet Macaques

Social Structure

• Troop size: 10-25 individuals
• Dominance hierarchy: One alpha male
• Female-bonded society — females remain in natal group
• Males migrate between groups
• Territorial — troops rarely overlap
• Communication: Diverse vocalisations, facial expressions, body postures

Reproduction

• Sexual maturity: Females at 4-5 years; Males at 6-8 years
• Gestation: ~180 days
• Single infant per birth (rarely twins)
• Birth interval: 2-3 years (long)
• Very slow reproduction — major challenge for recovery

Conservation Status

IUCN Red List

Endangered (EN) since 1988. Key concerns:

• Population decline of 25-30% over past three generations (35-40 years)
• Habitat fragmentation
• Small, isolated populations

Indian Legal Status

• Schedule I of the Wild Life (Protection) Act, 1972 — highest protection
• CITES Appendix I — highest international protection
• Hunting is illegal
• Trade is illegal

Population Trend

• Early 1990s: ~2,500 estimated
• 2008: ~3,000-3,500
• 2020s: ~3,000-4,000

Population has shown slow recovery since strict protection began, but remains vulnerable.

The Silent Valley Movement

The Lion-tailed Macaque became a symbol of environmental conservation during the Silent Valley Movement (1970s-80s):

The Controversy

In the 1970s, the Kerala government proposed building a hydroelectric dam in the Silent Valley (Kunti Puzha valley) — a pristine tropical rainforest in Palakkad district.

Proposed impact:

• Dam would submerge ~830 hectares of primary rainforest
• Destroy habitat of estimated 40-50 Lion-tailed Macaques (a significant proportion of world population)
• Affect other endemic species

Opposition

Massive opposition from:

• Kerala Sastra Sahitya Parishad (KSSP) — lead opposition organisation
• National Committee on Environmental Planning and Coordination
• Bombay Natural History Society
• International conservation groups
• Prominent scientists including M.S. Swaminathan, Salim Ali

Key Figures

• Dr. M.K. Prasad — KSSP leader
• Dr. Sathish Chandran Nair — scientist
• Ms. Sugathakumari — poet and environmental activist
• Dr. M.S. Swaminathan — agricultural scientist

Outcome

• 1983: Indira Gandhi cancelled the project
• 1984: Silent Valley designated as a National Park
• 1994: Declared part of the Nilgiri Biosphere Reserve

The Silent Valley Movement is considered one of India's most significant environmental victories — preserving a unique habitat and protecting the Lion-tailed Macaque population there.

Threats

Primary Threats

Habitat loss and fragmentation:

• Plantation agriculture (tea, coffee, cardamom, tea) encroaching on forests
• Hydroelectric projects in Western Ghats
• Road construction fragmenting habitats
• Urban expansion around forests

Human-wildlife conflict:

• Occasional raids on estate crops
• Road fatalities as troops cross highways

Slow reproduction:

• Long birth intervals make recovery difficult
• Small populations have genetic concerns

Isolation:

• Fragmented populations have limited genetic exchange
• Small isolated groups face local extinction

Indirect Threats

• Climate change affecting evergreen forest distribution
• Invasive species changing forest ecology
• Tourism pressure in some protected areas
• Poaching for pet trade (rare but occurs)

Conservation Efforts

Protected Areas

Major protected areas for Lion-tailed Macaque:

Conservation Programmes

Project Lion-tailed Macaque: A dedicated conservation program under the Ministry of Environment, Forest and Climate Change:

• Population monitoring
• Habitat restoration
• Corridor creation between fragmented populations
• Community engagement

Periyar Tiger Conservation Foundation: Special programmes for macaque conservation.

Research

Active research programmes by:

• Indian Institute of Science (IISc)
• Salim Ali Centre for Ornithology and Natural History (SACON)
• Nature Conservation Foundation

Other Macaques of India

For comparison, India has several macaque species:

The Lion-tailed Macaque is one of the most threatened Indian macaques.

UPSC Relevance

GS3 (Environment): Endangered species, endemism, Western Ghats biodiversity, conservation movements.

GS1 (Geography): Western Ghats ecology, Silent Valley.

Key Prelims facts:

• Scientific name: Macaca silenus
• Endemic to: Western Ghats (India)
• Also called: Wanderoo
• IUCN status: Endangered
• Wild population: ~3,000-4,000
• Schedule: I of Wildlife Protection Act, 1972
• CITES: Appendix I
• Distinctive feature: Silver-white mane + lion-like tail tuft
• Habitat: Tropical evergreen (shola) forests, 500-1,800 m
• Diet: Primarily frugivorous
• Silent Valley Movement: 1970s-80s (cancelled dam; saved LTM)
• Silent Valley NP: 1984
• Part of Nilgiri Biosphere Reserve
• Conservation leaders: M.K. Prasad, Sugathakumari, M.S. Swaminathan
• Project Lion-tailed Macaque: MoEFCC