One nice thing about the desert, you never know what you are going to see next. One minute nothing but rocks and sand in all directions, a lifeless Mars-scape; turn a corner and you're in a Garden of Eden, colorful plants, cactus, trees; the colors more precious now given the backdrop.

I guess the desert is still on my mind. Camped out near Joshua Tree, wind picking up, we leaned against huge, rounded boulders and stared at the night sky. Twelve million years ago, our campsite was an ancient sea bed, twelve thousand years ago a land bridge connected Asia and North America.

We stared at Comet Kahoutek through high-tech binoculars wondering about the peoples who first inhabited this desert. What would they have thought about this cosmic wonder? What were their concerns? Did they see anything close to the same world we see?

The next day we stopped in on civilization, replenishing our supply of food and books. And there staring back at us were the hands of our ancestors: the print to the left from a cave in France, and on the next page, an Anasazi hand from a rock not too far from our campsite. What can these hands reveal about our ancient brothers and sisters?

Nothing about a human hand is more human than the opposable thumb

As a matter of fact, a case can be made that the thumb's ability to oppose the fingers with force and dexterity is the main factor separating humans from other species on the planet: not intelligence - opposable thumbs. After all, dolphins have brains bigger than human brains, bigger in absolute size and bigger in proportion to their body. Dolphin brains also have a larger proportions of gray matter, the realm of so called "higher thinking." Think about that with your limited gray matter, you human you.

Apparently, according to biological measurements, dolphins have superior information processing equipment than do we humans. But dolphins do not have opposable thumbs. Dolphins do not rearrange the oceans. Dolphins are without technology (at least in any form that we can discern). We can debate who is better off in this regard, but one thing is certain. Humans, with their opposable thumbs, are the most technological types on the Earth. And the opposable thumb (human's tool making ability) is the key to this trait.

There are several factors to consider when examining someone's thumb

SIZE

Perhaps the most important factor is size. Is the thumb in proportion to the hand it is on? Big-thumbed people (all other factors in the hand being equal) have a strong inclination to go around rearranging everything. If they have a garden, they want a big one. Generals, CEO's, and others successful in their fields tend to have large thumbs. Small-thumbed people are more commonly found "under the thumb" of big-thumbed people. Large gardens seem like too much work.

ANGLE OF OPPOSITION

Another factor to consider is called the angle of opposition, how far away from the fingers does the thumb prefer to hang out. The further from the fingers, (the more the thumb can be found making a ninety degree angle with the fingers), the more industrious the owner. The closer to the hand and fingers (more like a thirty degree angle), the smaller the "grasp" and the less responsibility the person feels comfortable with.

SET

A third factor worth noting is called the set. The set of the thumb is the vertical distance from the thumb's insertion point down to the wrist. The greater this distance, the higher the set. Apes have high set thumbs. Far from the wrist and close to the fingers, apes thumbs have more difficulty opposing the fingers and are therefore less useful at tool making. Of course, apes do make tools. They use sticks to get bananas off trees, etc. But they do not pass their tools down from generation to generation as humans do.

The rule of thumb about sets is as follows: high set thumbs mean greater difficulty accomplishing tasks, low set thumbs mean tasks are more easily accomplished. You can certainly be successful with a high set thumb, it just means that you will have to work like the Dickens to get there.

So, how about our Pleistocene Pal from thousands of years ago?

The thumb from the cave in France is good sized, it fits well on this hand. Here is a person of determination and capability. However, the thumb is high set and in close. Thumbs of this size usually like to be lower towards the wrist and further out. Our friend, capable though (s)he may have been, is feeling a bit insecure about their life. Things are getting out of hand, out of control.

The top of the thumb is small in proportion to the lower section indicating difficulty in completing tasks. The likelihood is that (s)he can imagine doing more than (s)he is actually capable of handling. To use a meal-time analogy, the eyes are bigger than the stomach. Could this insecurity explain why our friend is in a cave, leaving messages for us to puzzle over?

Check out the Anasazi hand print below.

Another good sized thumb, very high set and held close to the palm. In all, Alana and I looked at exactly ten hand prints from ancient peoples. We found only one low set thumb and at least seven moderately high to high set thumbs, very different from hands today where the spread between low set and high set thumbs is more evenly distributed along a bell shaped curve.

Another good sized thumb, very high set and held close to the palm. In all, Alana and I looked at exactly ten hand prints from ancient peoples. We found only one low set thumb and at least seven moderately high to high set thumbs, very different from hands today where the spread between low set and high set thumbs is more evenly distributed along a bell shaped curve.

Are thumbs getting further out from the fingers (more opposable) and lower set?

Could it be that our ancestors were not as good at manipulating their environment as their descendants of today? Could it be that natural selection has removed those with the weaker thumbs? Or is it that, having created agriculture and the technological revolution, humans needed more assertive thumbs just to cope with daily life?

Or, am I looking through a biased telescope? Maybe our ancestors simply had less desire to control their environment, more desire to live with it. Then again, it's only ten sets of hand prints, too small a sample size to know anything with certainty.

But on a clear night out in the desert, I imagine myself sailing through the cosmos, my ten million mile tail stretched out across the Milky Way. Looking down on the planet I passed a thousand years ago, just a year in my time, comet time, it seems something from below is reaching up, trying to touch me, to know me. But it's hard to know for sure about such things. See you on the next go round.