The human hand is a remarkably versatile tool. One reason for this versatility: our thumb can be put in opposition to our other fingers. Consider how you would pick up a coin from a table. You would probably put your thumb on one side of the coin and your index finger on the other, then use a “pincer grasp” to pick up the coin. Even when you hold a pencil or piece of silverware, you use your thumb to oppose your other fingers. Imagine for a moment how you would deal with the world if your thumb was firmly taped to your hand. The only grasp you could use would be a finger-to-palm grasp: big and clumsy. So even though we don’t think much about our thumbs, they are a very valuable tool.

Many animals don’t have an opposable thumb, and so they cannot grasp objects with the precision that we can. This greatly reduces their ability to use tools, and tools are invaluable for human culture. A great many years ago, someone came up with the hypothesis that our opposable thumb was the reason why humans were so intelligent and successful. But what about chimpanzees? Anatomically, their thumb is much shorter than our own. Can they still use a pincer grasp? If so, the opposable thumb explanation for human success would be proven wrong.

Here Viki demonstrates that her short thumb can be put in opposition to her other fingers as she demonstrates a perfect pincer grasp. Another beautiful theory slain by an ugly fact!