I was seven or eight years old when I dug my first “dinosaur hole” — so called because I assumed that if I dug very far down I would discover dinosaur bones. Fortunately, my parents weren’t terribly dismissive of this idea; they mainly expressed a preference about where I dug — hopefully in the rear portion of our property, far from the house on our five-acre plot.

There are no surviving photos of my dinosaur holes, but this is a screenshot of Google Maps’ satellite view of several properties on our street. The red rectangle was our five-acre lot, and the red oval encircles the house I lived in from early 1979 through early 1984, in Choctaw, Okla. Click here to see a larger size.

It probably goes without saying, but I never found any dinosaur bones. Nor did I strike oil, discover underground cities, or find any other treasures — which you probably would have heard about by now. But there were definitely benefits: I got plenty of exercise, learned to cooperate and supervise (neighbor boys and two sisters helped me with these digs), and stayed out of my mom’s way for hours at a time. There were probably other valuable lessons in there too.

One thing I learned is that there is life underground.

(Dinosaur holes can’t take all the credit for imparting this knowledge to me. I also helped my father dig post holes for our fence, helped in the vegetable garden, and other outdoor activities.)

If you dig a few inches down with a small gardening spade, you’re likely to find several varieties of worms, perhaps a burrowing beetle or two, and maybe some ants. In Oklahoma and Texas, it’s almost always ants. Big red ones. Tiny brown ones. The kind that ignore you as well as the kind that attack you. In our yard in Choctaw, Oklahoma, just a little deeper would uncover the burrows of gophers (and/or moles). Once, the neighbor boys and I found a hibernating snake a couple of feet down — we scrambled for cover and allowed an adult to handle that.

And, though our first big dinosaur hole was in a smoothed-off grassy area, we quickly collided with thick roots. The nearest tree was at least thirty feet away, but its roots (or another tree’s roots) had searched far and wide for nutrition and moisture.

This particular gopher surfaced near me while I photographed a baseball game in Sasakwa, Okla. But it was very like the gophers I encountered as a child in Choctaw.

Copyright © 2009 by Wil C. Fry

If I had owned a microscope as a child, I would have discovered that any random cubic inch of soil under there was crawling with even tinier life. Mites and larva and the even tinier critters that feed on them. Not to mention microbes. Billions of microbes.

Decades later, teams of scientists around the world began discovering this too (alternate source link). Of course, they did what my 8-year-old self couldn’t do: they went really deep. Whereas my deepest excavations reached perhaps two meters below the surface, scientists recently have taken samples from five kilometers below the surface, using modern sophisticated boring equipment. And they keep finding life.

“Scientists estimate this subterranean biosphere is teeming with between 15 billion and 23 billion tonnes [between 33 trillion and 51 trillion pounds] of micro-organisms, hundreds of times the combined weight of every human on the planet.”

The Guardian

Scientists involved in this project say “the diversity of underworld species bears comparison to the Amazon or the Galápagos Islands”. Karen Lloyd, an associate professor at the University of Tennessee in Knoxville, said: “It’s like finding a whole new reservoir of life on Earth.” Apparently, seventy percent of all Earth’s bacteria and archaea (by mass) exist below the surface.

The research has further uncovered organisms that have lived for thousands of years, unmoving, with metabolism so slow and energy levels so low that biologists were surprised it was even possible.

“The scientists have been trying to find a lower limit beyond which life cannot exist, but the deeper they dig the more life they find.”

Wired

Once when I had dug a dinosaur hole deeper than my own height, my father joked that if I went much deeper, I would end up in China. I recall taking this comment seriously; I checked the globe in our living room. It turns out I would have ended up in the Indian Ocean (a little closer to Madagascar than to Perth) — assuming I could have kept going in a straight line and encountered no serious obstacles. (And for the latter half of that journey, I would have been digging upward rather than downward.) But the thousands-mile-long tunnel I pictured in my head then was mostly through uncolonized dirt and rock; I had no idea that life would be following me the entire way.

Add to this the knowledge that about half your body’s cells aren’t even human (and that 90 percent of your human cells are red blood cells and don’t contain your DNA), and I can only conclude: Life is weirder than we once thought.