Stump-Tailed Macaque, ThailandI’m just going to put this one out there and well… nature works in mysterious ways. That sac, shall we call it, under the chin is actually known as a cheek pouch and is used for storing food. You never know when you might need a snack. Function over style when it comes to the stump-tailed macaque. Photographed near Kaeng Krachan National Park on the Malay Peninsula of Thailand. Nikon D810 with Nikkor 200-400mm lens (at 200mm) ISO 800, f/4 at 1/320th of a second.