The call of White Cheeked Gibbon 

I head out to the Brookfield Zoo in Chicago. My intent was to photograph the 6 month old baby orangutan. However, for this moment, what got my attention was the call of the white cheeked gibbon. Incredibly loud for such a small creature. Would be an interesting experience to hear them in their natural habitat.
Apologies for the high grain footage and losing focus in some parts of the video. Lighting conditions weren't the best and it was hard to keep track of the primates in the camera's viewfinder.