Western Hoolock Gibbon

Names & Nicknames: Western hoolock gibbon, White-browned gibbon, Mishmi Hills hoolock gibbon

Size: Hoolocks, such as the Western hoolock, are the second largest species of gibbons, only behind the mighty Siamang gibbon. All three species of hoolock are similar in size, reaching around 60-90cm in height and 6–9kg in weight. That's around the size of a 1-year-old child - but with longer limbs!

Smell: Primates like gibbons tend to be more visual animals, using sight to find food and communicate as opposed to smells like Komodo Dragons or Giraffes. Though hoolock gibbons have glands in their sternums and groins, which researchers believe may be used to communicate by leaving smelly secretions.

Communication: As mentioned above, we don’t know much about whether they communicate with smells, but it's hard to miss their main form of communication: noise! Western hoolocks communicate mainly through loud songs that can travel miles through the jungle. They often sing a duet with their partner, or unmated hoolocks may prefer belting out solo numbers. The true rockstars of the jungle!

Favourite HANGout: These swingers are highly arboreal, which means they spend most of their time hanging out in trees. Their trees of choice are dense, undisturbed forests with continuous canopies in Northeast India, Bangladesh, and parts of Western Myanmar. Unfortunately, dense undisturbed forest is a habitat that is becoming harder and harder to find, see the red flag section for more details...

Favourite Snack: Leaves, shoots, eggs, insects, and even small vertebrates. Given the choice, however, their absolute favourite snack is juicy ripe fruits. Some of their favourites include persimmons and figs.

Eating Habits: Western hoolocks actually play a very important role in helping out the forest. After munching on some tasty fruit, it eventually makes its way from the mouth to the… other end. The seeds are mostly undigested by the gibbon and once they come out, they are left far away from their parent plant, with a nice dollop of gibbon fertiliser for good measure! Helping spread seeds throughout the jungle and keeping the jungle healthy and green.

Toilet Humour: Ahhh, the sun is shining, the coffee is brewing, it’s the start of another beautiful day, but what’s that … a commotion in the bowels and nature is calling! If you have ever had a case of the morning rumbles, well maybe you are more similar to a western hoolock gibbon than you might think. Like other gibbons, Western hoolocks do their business in the mornings as they get ready to leave your sleeping site, so if you are taking a morning stroll through the jungle, watch out for any falling debris from above!

Love Language: Perfectly on brand for these rockstars, Western hoolock courtship involves a whole lot of noise. When the time is right, a Western hoolock gibbon ventures out of its family group to try and start a new family. Courtship involves loud songs, often sung as duets between a flirtatious pair, and they'll form a monogamous bond that will last for life, singing together to reinforce this bond.

If you see them: You're definitely more likely to hear them rather than see them. Their calls can reverberate for miles and miles in the jungle homes.

Red Flags: The two main threats to Western hoolocks are habitat loss and poaching. This species requires dense connecting forests with a variety of different fruit trees and plenty of space for family groups to have their own territories. As more and more of this habitat is cut down and fragmented due to deforestation, these gibbons have less and less space to live in. Even the little pockets of suitable habitat might not be entirely safe, however, as this species is also illegally hunted so the adults can be killed and sold for meat and traditional medicine, and the babies sold as pets. If this keeps up, the jungles may sadly be silent.

Epic Journeys: Western hoolocks are homebodies, creating territories between 0.8 and 400 kilometres squared. They will live in a monogamous pair or in a small family group made up of the mating pair and their children. They can't sit still, however, as they constantly need to find food, so they travel around a kilometre each day, swinging through the trees at up to 20mph in search of the juiciest fruit.

Glow-up: Around every three years, a female Western hoolock will give birth to a single baby gibbon. Mums will carry the young ape over the next two years until they're gradually weaned off their mothers and become more independent. They'll stay with their parents and potentially some siblings until around eight, when they are old enough to go into the forest and find their own singing partner.

Facts: Gibbons love to sing, and they love to sing LOUD. However, it turns out that humans may be dampening their songs. Researchers noticed that Western hoolock gibbons stopped singing in the dry season. Originally it was thought that they'd gone locally extinct. But a month later, when the wet seasons started, the songs of these gibbons echo'd through the forest again. Turns out they hadn't gone anywhere but stopped singing when hunters entered the forests in drier weather. When the rain came and the hunters had left, they could sing again! Hopefully through conservation efforts, we can make sure the forests can have gibbons singing again all year long!

Who are they in the friendship group: Athletic. Social. Loud.