Taxonomy
Assessment Information
- IUCN Red List Category and Criteria
- Least Concern ver 3.1
- Assessment language
- English
- Year published
- 2020
- Date assessed
- 2015-11-21 00:00:00 UTC
Listed as Least Concern as the species has a relatively wide distribution, is common, and the threats that it is facing are probably not resulting in a significant population decline.
Geographic Range
This species occurs in the monsoon forests of North Western Frontier province of Pakistan, through the high Himalayan elevations (1,500-4,000 m) of India, Nepal and up to the Sankosh River in Bhutan.
Population
Habitat and Ecology
This species inhabits subtropical to temperate broad-leaved forest, pine forest, riparian mountain forest, riverine forest, rocky outcrops, and scrub jungle (Molur et al. 2003). A. Kumar (pers. comm.) has observed this species at 3,500 m, but has reports of its occurrence above this elevation, and it may be present up to 4,000 m. It is diurnal, terrestrial, arboreal, and folivorous. It is a diurnal and mainly terrestrial species, but may prefer arboreal canopies to flee from danger. Individuals are sometimes known to prefer barren rock cliffs for warmth.
Langurs inhabit semi evergreen Sal (Shorea robusta), and alpine cedar forests. They could range as high as as 3,500-4,000 m and could well survive harsh winters and rainy summers in July-October and an annual rainfall as high as 2,500 m. Most of their diet is composed of leaves (40-60%), and the rest of fruits (20%), ripe, unripe, herbaceous fruits. Other constituents are seeds, storage organs, roots, flowers, cambium, bark, twigs, coniferous cones, moss, lichens, epiphytic fern, young bamboo shoots, rhizome, grass and invertebrate animals. They prefer young leaves of broad-leaved deciduous trees than of evergreen trees. Seasonal variation in food preference is well pronounced. In spring and summer, when their diet is diverse, they feed on leaf clusters of Zanthoxylem nepalense, young leaves and bark of Jasminum humile, acorns, young deciduous leaves, and pine cones. In monsoon, feed on young deciduous leaves and fruits, while in autumn consume unripe fruits, seeds and fleshy ripe fruit, herb leaves and fruit, fleshy plant tissue, cultivated potato Solanum tuberosum. In winter, leaf buds, fruits (ripe) of Cotonester frigidus, Berberis aristata, leaf buds of Sorbus cuspidate, herbs and pinecones.
Birthing is concentrated between late winter to early spring and most mating happens between July-September. This arrangement allows for the langur infants to grow strong to survive their first winter. Besides, winters also mean migration down hill and the independent mobility of infants allows for easy migration for the both the mother and the infant. The inter-birth interval is usually 25 months, until the female gets pregnant and when she weans her infant. Inter-birth intervals are shorter when the infant dies and the female becomes receptive to mate again.
Like other Himalayan species, this species lives in multi-male, multi-female groups. Group sizes range between 4-47 individuals with 1-4 adult males and the female sex ratio 1-1.5-1.7. Larger groups may split while maintaining contact through intermittent call by males. The annual home range is 1,275-12,700 ha due to seasonal migration up and down the mountain. The call of dominant males is a ‘Wao’ or ‘Ua’ and these langurs don’t woop like the southern Indian or plain dwelling langurs. No infanticide during troop takeover was observed, despite 32 months of observation in Junbesi-Ringmo between Kathmandu and Nepal-Sikkim Border.
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Threats
The taxon, although widely distributed across the Himalayas, is subject to various threats from human interference including logging, habitat loss, fires, human habitations, expansion, developmental activities, encroachment, and war, which makes it susceptible to declines in areas subject to such threats (Molur et al. 2003). Hunting is an important threat in China (Z. Yongzu pers. comm.); this species is used in traditional native “medicine” in Tibet. This species is a dry meat delicacy in Nepal.
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