Biology
The Digestive Physiology of Foregut Fermentation in Howler Monkeys
Quick fact
Howler monkeys are the only New World primates that use foregut fermentation, and they also have the most diverse gut microbiome of any monkey to help them break down the tough leaves they eat.
Why this is interesting
Howler monkeys are famous for their loud calls, but the real secret to their success might be in their stomachs—a chamber that works like a fermentation vat, not a simple stomach you'd expect in a monkey.