SCOTT SIMON, HOST:

There's a spot on the grasses of the Serengeti in which the steps of small three-toed ancestors of horses seem to fall into the same path as the footprints of early hominids. Were they walking together, hunting together, or did two groups just encounter each other more than 50 million years ago and decide they'd walk on together? The author of a new book says it's impossible to tell but irresistible not to speculate that these fossilized prints depict an extraordinary partnership that's lasted for centuries. Wendy Williams' book is "The Horse: The Epic History Of Our Noble Companion." And Wendy Williams, the author and journalist, joins us from member station WCAI in Woods Hole, Mass. Thanks so much for being with us.

WENDY WILLIAMS: Well, I'm so delighted you liked the book.

SIMON: Why do horses have hooves, not paws or claws or fingers?

WILLIAMS: You know, that's a question that I've been wondering about maybe since I was 5 years old. I don't think many people really think about it, but horses are the only animal on earth that has a - a hoof.

SIMON: Yeah.

WILLIAMS: Other animals have hooves on - at the bottom of each leg, but the horse has managed to evolve just one hoof. And the answer to that question has to do with all kinds of changes on the earth - tectonic collisions and the rising of mountains and the explosion of volcanoes and the spread of grass and cold weather and warm weather and then cold weather again. It's all these very, very complicated energy systems that ended up giving us the horse that we have in the modern world today.

SIMON: You learned a lot as a youngster from a horse named Whisper, didn't you?

WILLIAMS: Oh, yes, Whisper. So in those days, I had a very small barn that I had to carry water back and forth from because there was no water down at the barn. In the summer time, of course, you can just run a hose down there. But in Vermont in the winter time, it's minus-10 degrees, so that doesn't work. One day, I thought I was being extremely clever by bringing the horses up to the water faucet on the side of the house and putting buckets under there for them to drink their fill. And I guess in the short run I was being somewhat clever. But in the long run, it didn't pay off. The reason was that one day when I got up and I was a little bit grumpy because it was minus-10 degrees outside, I decided to have a second cup of coffee instead of run down immediately and water and feed the horses. And as I wrote in the book, as any barn hand knows, this will cause consternation in the stalls. So while I was having my second cup of coffee, Whisper comes leaping over the fence. I had no idea he could even jump, let alone jump like that with such elegance and just come trotting right up to the side of the house and take his hoof and pow, pow, pow on the water faucet until he managed to turn the water on. Of course, I learned my lesson because what I did not want to do was pay for a plumber to have to come and fix the water faucet. So I managed to get up from then on, on time to bring them their food and water.

SIMON: For years, scientists thought that stallions had - they even use the terminology harems of mares. You think that might've been the product of modern scientists having male blinders on.

WILLIAMS: I don't want to accuse anyone here. But let me just put it this way - stallions are major-league drama queens. And when stallions have at it with each other, the mares don't pay much attention because they're used to it. But we pay attention, we look at it and we imagine that that kind of arguing on standing on two hooves...

SIMON: Yeah.

WILLIAMS: ...And hitting the other stallion with the front hooves, we imagine that that they control things. But in fact, they have some input into a band of mares, but the mares tend to make a lot of their own decisions. And if the stallion wants to be part of that, he has to just come along because they're going to go where they're going to go. If they want to get water, they're going to go get it. If they think there's a better place to eat grass, they'll do that. And the stallion is allowed to come along. But he's certainly not the major decision-maker in a band of horses.

SIMON: Yeah. This substantially turns on its head the kind of folk myth that we've had for years, right?

WILLIAMS: Well, I grew up with that. I think I've probably read every horse book for kids that was ever written. And I grew up reading that the stallion protected the herd and that the stallion would fight off all the enemies. Some stallions do fight off enemies to some degree. But to be honest, the scientist I interviewed, Jason Ransom, said that he'd seen some stallions take off in the face of danger as much as he'd seen them defend the band.

SIMON: We humans like to think we've domesticated horses to haul things and plow fields and help us rove the earth. But you suggest there might be something more complicated going on.

WILLIAMS: I don't to think it's a black and white kind of thing. I don't think a horse is either domesticated or wild. I think they're just a lot of nuances in that relationship, and that's not just me. Scientists who study these things in all kinds of animals are beginning to understand the nuances in a relationship. And they're beginning to understand that many animals, horses included, may actually choose to be with us.

SIMON: Are we on the verge of what amounts to a kind of - a new understanding that suggests a new partnership between humans and horses?

WILLIAMS: I'm sure that's happening. It's amazing to me - I had to set up a Facebook site because my publisher wanted me to, and I am astonished by the number of people all around the world who are working in this new way. As I say, it involves a lot more compassion for the horse. It involves a lot more communication with the horse.

SIMON: Because we don't rely on the horse for transportation and plowing, that kind of close-working partnership anymore. But yet the popularity of the horse is undiminished.

WILLIAMS: People still love horses. It's just something about their beauty, their grace, their affinity for speed. You know, we are traveling animals and so are the horses, so we just naturally belong together.

SIMON: Wendy Williams' book is "The Horse: The Epic History Of Our Noble Companion." Thanks so much for being with us.

WILLIAMS: Well, thanks for asking me.

(SOUNDBITE OF SONG, "TENNESSEE STUD")

DOC WATSON: (Singing) The Tennessee stud was long and lean, the color of the sun and his eyes were green. He had the nerve and he had the blood, and there never was a horse like the Tennessee stud.