Hoolock hoolock
Silhouette: PhyloPic
In 3 days ~90% in a week >90%
The western hoolock gibbon (Hoolock hoolock) is a primate from the gibbon family, Hylobatidae. The species is found in Assam, Mizoram, and Meghalaya in India, Bangladesh, and Myanmar west of the Chindwin River. Mootnick and Groves stated that hoolock gibbons do not belong in the genus Bunopithecus, and placed them in a new genus, Hoolock. This genus was argued to contain two and later three distinct species, which were previously thought to be subspecies: H. hoolock, H. leuconedys, and H. tianxing. A larger evolutionary distance was later found to exist between these three species and the white-handed gibbons than between bonobos and chimpanzees.
A new subspecies of the western hoolock gibbon has been described recently from northeastern India, which has been named the Mishmi Hills hoolock gibbon, H. h. mishmiensis. Like other gibbons, hoolock gibbon pairs produce a loud, elaborate song, usually as a duet from the forest canopy, in which younger individuals of the family group may join. The song includes an introductory sequence, an organising sequence, and a great call sequence, with the male also contributing to the latter (unlike in some other... Wikipedia →
Song1:10
Bangladesh · 2024
© Ding Li Yong · XC961312 · CC BY-NC-ND 4.0
Call0:37
India · 2024
© Lars Lachmann · XC1045821 · CC BY-NC-SA 4.0
Recording2:33
India · 2025
© capepolly · iNaturalist · CC BY-NC 4.0
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Namdapha National Park | 🇮🇳 India | |
| 2 | Kaziranga National Park | 🇮🇳 India |
| # | Zoo / Centre | Country | |
|---|---|---|---|
| 1 | Fota Wildlife Park | 🇮🇪 Ireland | |
| 2 | 西霞口神雕山野生動物世界 | 🇨🇳 China |
Likely
About 50% of wildlife watchers report a Western Hoolock Gibbon sighting in Namdapha National Park on a given day, based on 16 verified sightings from GBIF citizen-science data from 2019 to 2026. Over three days the chance rises to about 90%, and over a week to over 90%, if each day is a fresh chance.
March and April
In those months about 70% of wildlife watchers report a Western Hoolock Gibbon in Namdapha National Park on a given day, against about 10% in February, the lowest month. June to September have too few records to rate.
Between 3 and 6 am
Across all the parks we cover, that three-hour window holds the most Western Hoolock Gibbon sightings with a recorded time, and about 6 in 10 of them come between 6 pm and 6 am: it is most active around dawn and dusk.
Yes
Of the 2 parks where we can rate Western Hoolock Gibbon sightings, Namdapha National Park has the highest daily chance: about 50%. Next come Kaziranga National Park (India, about 50%).
GBIF citizen-science records
It is estimated from how often the Western Hoolock Gibbon is recorded against all the mammals logged in Namdapha National Park (16 verified sightings from 2019 to 2026), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
