Monkeys and Secret to Better Termite Fishing.

 Under a grant from the National Council for Scientific and Technological Development, Souto and his colleagues studied a group of six tufted blonde capuchins in the northeastern Brazil Atlantic Forest in the state of Paraiba.

This species is critically endangered and was once even thought to be extinct, until small groups like this one were rediscovered. At present, it's estimated that only around 180 of the golden-hued monkeys exist.

The monkey's diet consists of fruits, spiders, small vertebrates, an occasional sweet sip of sugar cane, and insects, including termites. The scientists noticed that three male blonde capuchins used a unique, multi-step method to extract termites from nests located high in the forest canopy, up to around 33 feet above the ground.

With his semi-prehensile tail wrapped around a tree branch, the monkey sits in a squatting position on a limb. The individual next taps on the sides of the termite nest before breaking a branchlet off the tree. Using a rotating motion, the monkey inserts the stick into the nest. Upon retrieval, he inspects the stick and then eats the attached termites.

"When a nest is disturbed by an object breaking into its walls, soldiers (of this Brazilian termite species) swarm at the place where the break occurs," Souto explained. "Our results indicate that tapping the walls before inserting a stick increases the number of extracted termites, possibly because soldiers enter into a state of alert prior to the break, enhancing their response toward the strange object."

Tapping isn't the only secret to better termite fishing. When the researchers tried out the insect-hunting method themselves, they determined that rotating the stick also prevented this tool from breaking. Souto believes the rotation, like a drill, causes abrasion of the nest surface material, helping to create the needed hole.

The findings add to our knowledge of how tool use evolved, and continues to evolve, in primates. Previously it was thought that our ability to walk with two feet on the ground, freeing up our hands, gave us a technological edge over other primates. Now it's known that manual dexterity can lead to successful tool use off the ground. The researchers also suspect that having a varied diet, as these blonde monkeys do, helps with tool innovations.