Bearded Capuchins are a species of monkey that live in the forests of Central and South America. They are known for their distinctive, bushy beards and their ability to use tools. One of the most impressive things about bearded capuchins is their ability to crack open nuts. Using a hammerstone and anvil, they can open tough-shelled nuts such as Brazil nuts and coconuts.

Here's how they do it:

>1. Select the right tool. Bearded capuchins will carefully choose a hammerstone that is the right size and shape for the nut they want to crack. The hammerstone should be heavy enough to break the nut, but not so heavy that it is difficult to handle.

>2. Find a suitable anvil. The anvil is a stationary object that the bearded capuchin will use to crack the nut. It can be a rock, a tree trunk, or even another bearded capuchin. The anvil should be sturdy and stable so that it does not move when the hammerstone is struck against it.

>3. Position the nut. The bearded capuchin will place the nut on the anvil in such a way that it is stable and will not roll away. The nut should be positioned so that the hammerstone will strike it directly.

>4. Crack the nut. The bearded capuchin will then use the hammerstone to strike the nut. The force of the blow will cause the nut to crack open, revealing the edible kernel inside.

>5. Eat the kernel. Once the nut is cracked open, the bearded capuchin will eat the kernel. The kernel is the nutritious part of the nut, and it is a valuable source of food for bearded capuchins.

The ability of bearded capuchins to crack nuts is a testament to their intelligence and their ability to use tools. This skill allows them to access a valuable source of food that would otherwise be unavailable to them.