Heard but not seen: The White-browed Gibbon

[Something warm and cuddly hanging from a tree, as Christmas approaches!]

Of all the apes, gibbons are the hardest to see but the easiest to hear: listen to this troop calling, and imagine hearing it deep in the forest:

Seeing them is another matter.

We were at the Hoolock Gibbon Sanctuary two hours east of Kaziranga, which has a stable and even  increasing population of White-browed Gibbons, more properly known as Western Hoolock Gibbons, Bunopithecus hoolock.

They move around high in the canopy, brachiating*:


But getting a clear view let alone a close-up is hard. This is either a male or a juvenile: both are black with dramatic white eyebrows, just visible in this photo, most of which is a picture of his/her bottom.

Western Hoolock Gibbon

But every now and then you get lucky: look at the astonishing length of those arms.


Their arms are almost twice as long as their legs, and when they descend to the ground (rarely) they have to hold their arms above their heads. On the ground, they are about a meter tall, the height of a small child.

The mature females are naturally blonde (so teenage gibbon girls don’t need peroxide) , and note the bulging biceps that come from doing chin-ups all day long:

Western Hoolock Gibbon

Here is a closeup of the female and baby:

Western Hoolock Gibbon

Hoolock gibbons are thought to mate for life, and a family group has an adult pair and 1-4 juveniles of varying ages. They are considered endangered, numbering around 100,000 globally, and 90% of those are in Myanmar. Their population has fallen by about 50% over the last 40 years (three generations), largely due to habitat loss, and this decline is forecast to continue.

*Brachiating is using only your arms to move around, like a gymnast on the horizontal bar.

PS: Apes, unlike monkeys, have no tails. Gibbons are Lesser Apes, as opposed to the chimps, bonobos, orangutans, gorillas, and humans, all of which are Great Apes, aka Hominids.

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