We call human beings Homo sapiens, but I think there might be more than one species of us.
This is not a very scientific thought. But thoughts like this come to me when I get around somebody like Michael Engel. He's assistant curator of entomology at Kansas University's Natural History Museum.
Now it's not Engel's appearance that sets him apart. His face is pleasant, his voice mild. He doesn't have an extra head or anything.
His difference has to do, in part, with a passionate interest in dead insects. Not the kind that gather at the bottom of the front-porch light fixture, but the kind that lived hundreds of millions of years ago.
His difference from us also rests on his encyclopedic memory of the details of the wings, jaws, heads and other standard issue of insects so totally dead there's no way to imagine the lengths of time involved.
Engel stocks his memory by seeing and studying insect fossils -- parts of them or wholes -- in museum and in field. And what he cannot see, he reads about.
"It's not like preparing for a test," he says. "I don't make up flashcards and go over the same material time and time again. But I make myself knowledgeable about everything that's known about the evolution of each lineage of insects."
This means that when his book, "Evolution of the Insects," comes out in February or March from Cambridge University Press, it'll be a work almost no other North American Homo sapien could have written.
Except for maybe the only other North American expert on fossil insects, Dave Grimaldi, his co-author.
The book is months late, by the way. With good reason.
Last year at this time, the two men published, in the journal Nature, their discovery of the oldest insect remains in the world.
They made the discovery looking at specimens in a Scottish museum. The parts were entombed in flint that had been dug up in 1924.
The scientists saw them for what they were: fragments of an exploded insect head more than 400 million years old.
That's 30 million years older than the second oldest fossil insect ever found.
Details about the head make the scientists believe the insect flew -- 80 million years before anyone thought insects flew.
"This was a eureka moment," Engel says, "except, unlike Archimedes, we didn't strip naked and run down the street."
The finding meant rewriting part of their book.
Then came another happy finding, and it led to more rewriting. Engel identified the oldest beetle fossil ever found in North America. He published a paper on that in mid-January.
The media come to your door when you find the world's oldest anything. And most people would get a big head if CNN called, right? But Engel's not most people.
His admiration seems to be less for himself than for the triumph of insects. They own the planet -- and have, Engel says, for at least 350 million years.
Today, they make up two-thirds of Earth's species. There are more kinds of beetles than of plants.
You snuff out Homo sapiens, and other species will flourish, Engel says. But if you kill off pollinating insects, plants die -- and then us.
With measured respect, Engel says, "The smaller things run the world."
Most of us don't come close to thinking about things in those terms, much less feeling them as fully as Engel does.
We're talking here, at the least, about a different species of mind.