Here’s a full scientific and natural history overview of the Stump-tailed macaque (Macaca arctoides), a rugged-looking primate of South and Southeast Asia:

**Stump-tailed Macaque (Macaca arctoides)**

Taxonomy & Classification

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Cercopithecidae (Old World monkeys)
Genus: Macaca
Species: M. arctoides

General Description

The stump-tailed macaque, also known as the bear macaque, is a large, stocky monkey named for its short tail and bear-like appearance.

Size:
- Head-body length: 45–65 cm
- Tail length: 3–7 cm (short, almost vestigial)
Weight:
- Males: 9–10 kg (can exceed 15 kg in some regions)
- Females: 7–8 kg
Appearance:
- Coarse, dark brown to black fur, often shaggy.
- Face bare, initially pinkish but turning redder with age.
- Strong limbs, well-adapted for climbing and terrestrial movement.
- Very short, “stump-like” tail (hence the name).
Lifespan: 25–30 years in the wild; longer in captivity.

Behavior & Lifestyle

Social Structure:
- Live in multi-male, multi-female troops of 20–60 individuals.
- Strict dominance hierarchies, but females are often more socially tolerant than in other macaques.
Activity:
- Diurnal and both arboreal and terrestrial, though more time is spent on the ground.
Diet: Omnivorous and opportunistic.
- Fruits, seeds, leaves, roots, fungi.
- Insects, small vertebrates, and bird eggs when available.
- Often raid crops in agricultural areas.
Reproduction:
- Non-seasonal breeders (unlike some macaques).
- Females show subtle signs of fertility rather than large swellings.
- Gestation ~6 months; usually a single infant.

Habitat

Occupies evergreen and mixed deciduous forests, bamboo thickets, secondary forests, and montane forests up to ~2000 m elevation.
Also known to survive in fragmented or degraded forest near human settlements.

Geographic Range

Distribution: Found across South and Southeast Asia.
Countries include: India (Northeast), Bangladesh, Bhutan, Myanmar, Thailand, Laos, Cambodia, Vietnam, southern China (Yunnan, Guangxi), and Malaysia.

Ecological Role

Seed Dispersal: By consuming fruit and excreting seeds, they aid in forest regeneration.
Predator-Prey Dynamics: Preyed upon by leopards, dholes, large snakes, and raptors.
Human Interaction: Can act as crop pests but also maintain ecological balance by dispersing plant species.

Special Adaptations

Stump Tail: A reduced tail prevents injury when moving through dense vegetation or on the ground.
Facial Coloration: Older individuals develop bright red faces, thought to signal maturity and dominance.
Flexible Diet: Ability to exploit a wide range of foods, enabling survival in diverse habitats.

Conservation Status

IUCN Red List: Vulnerable
Population Trend: Decreasing.
Main Threats:
- Habitat loss due to logging, agriculture, and infrastructure expansion.
- Hunting for bushmeat and traditional medicine.
- Capture for the pet trade.
Conservation Measures:
- Protected in many national parks and reserves.
- Listed on CITES Appendix II (trade regulated).
- Community-based conservation efforts needed in agricultural landscapes.

Interesting Facts

The reddening of the face with age is so distinctive that older individuals can be identified at a distance.
Despite their size, stump-tailed macaques are agile climbers but spend much time foraging on the ground.
They have been observed washing food in streams, a behavior shared with some other macaque species.
Locally referred to as “bear monkeys” because of their thick fur and bear-like profile.