This is a white-handed gibbon in Bukit Lawang National Park, Sumatra, Indonesia. These lesser apes were easily among the most difficult to photograph primates that I’ve ever come across. For several days I had unsuccessfully been trying to get a shot. I’d see the gibbon for a second and then it would be gone (or it would be too far away, or hiding behind foliage, etc). They were very wary of humans and usually fled before I even knew they were there. It became a bit of an obsession to get a shot and eventually I was rewarded this one quick look — not perfect, but in focus and in decent light. Gibbons are extremely agile in the trees with their long arms and after one click of the shutter this one disappeared.