Here’s a comprehensive overview and description of the Stump-tailed Macaque (Macaca arctoides) — a fascinating and distinctive Old World monkey native to Southeast Asia.

🐒 Stump-tailed Macaque (Macaca arctoides)

Taxonomy

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Cercopithecidae
Genus: Macaca
Species: Macaca arctoides
Common names: Stump-tailed macaque, Bear macaque, Red-faced macaque

General Description

The Stump-tailed macaque is a stocky, powerful primate recognized for its bare red or pinkish face, short tail, and dense fur. It has a somewhat bear-like appearance, which explains its nickname “bear macaque.”

Body length: 45–65 cm (males larger than females)
Tail length: 3–9 cm — short and “stump-like”
Weight:
- Males: 10–15 kg
- Females: 7–12 kg
Fur color: Dark brown to black, often shaggy or woolly in texture
Face: Hairless and typically reddish or dark pink, becoming more vivid with age or emotion
Distinctive features:
- Short, almost invisible tail
- Deep-set eyes and broad muzzle
- Strong limbs for climbing and ground movement

Distribution and Range

The stump-tailed macaque is native to Southeast and South Asia, with a wide but fragmented range.

Geographic range:

India (Assam, Arunachal Pradesh, Meghalaya)
Bangladesh
Myanmar
Thailand
Laos
Vietnam
Cambodia
Southern China (Yunnan)
Malaysia (Peninsular regions)

They inhabit evergreen and semi-evergreen forests, from lowland rainforests to mountain forests up to 2000 m altitude.

Habitat

Preferred environments:
- Tropical and subtropical broadleaf evergreen forests
- Montane and hill forests
- Occasionally in secondary growth and bamboo forests
They are semi-terrestrial, spending much time on the ground but also climbing trees for food and safety.

Behavior and Ecology

Stump-tailed macaques are social, intelligent, and robust primates, living in large, cohesive groups of 20–60 individuals, led by a dominant male.

Daily Activity

Diurnal: Active during the day
Spend most of their time foraging on the ground, but sleep in trees at night.
Move in groups with coordinated social hierarchy.

Social Structure

Female-bonded groups: Females remain in natal groups, while males disperse at maturity.
Hierarchy: Both males and females have clear dominance ranks.
Grooming: An essential behavior that strengthens social bonds and reduces stress.

Communication

Communicate via facial expressions, vocal calls, and body language.
The red face and expressive eyes are key components of visual signaling.

Diet

Omnivorous, with a diet that varies by season and habitat.

Primary foods:

Fruits and seeds
Leaves and buds
Roots and tubers
Insects, frogs, and small vertebrates
Bird eggs and agricultural crops (where habitat overlaps with farms)

They are opportunistic feeders, playing an important ecological role in seed dispersal.

Reproduction

Mating system: Promiscuous (both sexes mate with multiple partners)
Breeding season: Year-round, with peaks in cooler months
Gestation period: ~175 days (5.5–6 months)
Offspring: Usually one infant per birth
Weaning: Around 8–12 months
Sexual maturity:
- Females: ~4 years
- Males: ~6 years
Lifespan: Up to 25 years in the wild, 30+ years in captivity

Females display sexual swellings when fertile, and infants are cared for by the mother, sometimes aided by other females.

Predators and Threats

Natural predators:

Leopards, pythons, and large birds of prey

Main threats:

Deforestation and habitat loss
Hunting and poaching (for meat and traditional medicine)
Capture for pet trade or biomedical research
Conflict with farmers (crop raiding)

Conservation Status

IUCN Red List: 🟥 Vulnerable
Population trend: Decreasing

Major conservation concerns:

Rapid habitat destruction due to agriculture and logging
Fragmented populations reducing genetic diversity

Protection measures:

Listed on CITES Appendix II (trade controlled)
Occurs in many protected areas across its range (e.g., Kaeng Krachan NP in Thailand, Nam Et–Phou Louey NP in Laos)
Some rehabilitation and breeding programs exist in Southeast Asia

Ecological Role

Acts as an important seed disperser for many tropical tree species.
Helps maintain forest regeneration and ecological balance.

Identification Summary

Feature	Description
Scientific Name	Macaca arctoides
Common Names	Stump-tailed macaque, Bear macaque
Size	45–65 cm body, 3–9 cm tail
Weight	7–15 kg
Color	Dark brown fur, red face
Behavior	Ground-dwelling, social, intelligent
Diet	Omnivorous (fruits, leaves, insects)
Habitat	Tropical/subtropical forests
Range	South and Southeast Asia
Conservation Status	Vulnerable

Interesting Facts

The bare red face becomes darker and more vivid with age.
Their short tail helps identify them instantly among macaques.
They are excellent swimmers and sometimes bathe in forest pools.
Despite their fierce appearance, they are shy and non-aggressive toward humans when unprovoked.
Their thick fur allows survival in cooler, montane forests compared to other tropical macaques.

Summary

The Stump-tailed macaque (Macaca arctoides) is a strong, red-faced primate adapted to both forest floor and canopy life. Its intelligence, complex social behavior, and ecological importance make it a vital part of Asian tropical ecosystems. Sadly, habitat loss and hunting threaten this species, underscoring the importance of protecting Southeast Asia’s forests and wildlife.