They can use this tail as an extra arm to grip or even hang from branches—no Old World monkeys have such a tail. A gripping tail is particularly helpful to howler monkeys because they rarely ...

What an adventure. And all because of his curiosity about the Mexican howler monkey! (SR for Tagtik/Source: Ahora Tabasco Noticias/Illustration picture: Photo by Andrey Stakhovskiy on Unsplash ...

My adventure of a lifetime began in 2015 when I was asked to follow the tree-top lives of Costa Rica’s gravity-defying howler monkeys (Alouatta palliata palliata). Image by Justine Allan.