One would be hard-pressed to find a human who hasn’t hit, kicked, or thrown a ball. John Fox, a Harvard PhD in anthropology, has spent the last decade researching the roots of this ubiquitous orb, which goes back a few million years. Why are we all so fixated on balls? Among Fox’s findings: “Animals that play are…smarter and more socially intelligent than those that don’t.” For the full evolution of balls, read Fox’s new book “The Ball: Discovering the Object of the Game.” Then watch the  follow-up documentary “Bounce: How the Ball Taught the World to Play” to be released next year. But first, more details about the world’s most playful inanimate object:

Discovery: You were out playing ball with your son when you had a “lightning bolt” moment about the ball. What happened?

John Fox: When my son asked that innocent question, “why do we play ball?” we instantly went from doing something routine and prosaic to something exotic and strange—tossing this sphere of cork and yarn back and forth for no obvious reason. As an anthropologist, I’d spent years thinking about the anthropology of sport but in a somewhat detached, academic way. My son’s question awoke in me an innocent, playful curiosity about the subject that I’d never allowed myself to have before.

D: Where did you travel to research this book?

JF: My book research covers every inhabited continent, but my travels took me to a Florida marine park, a remote Scottish isle, a French chateau, West Mexico, the Onondaga Indian Nation, Washington, DC, Massachussetts, rural Ohio, and the Ecuadorian Amazon. Oh, and there was that lost weekend driving to Rome, New York, to consume cheap beer and hoagies at the World Series of Bocce.

Photo: Jerome Thelia/Bouncethemovie.com

D: What is the most bizarre ball you encountered?

JF: The French of the 16th century stuffed their tennis balls with beard hair. The Australian Aborigines played a traditional form of football with a ball made from a kangaroo scrotum. But perhaps the weirdest comes from our own national pastime. In the early days of baseball in the mid-19th century, some teams in the lake regions of the Midwest played with balls made from sturgeon eyeballs wrapped in yarn and leather! I imagine fathers telling their sons: “Keep your eye in the ball!”

D: What is the most interesting statistic about balls?

JF: One of my coolest trips was to the Wilson Football Factory in the town of Ada, Ohio, where every NFL football has been made since 1955. I learned there that a single cowhide can typically yield 10 footballs. And that every NFL game goes through around 40 regular balls and 12 kicking balls. So I ran the math to determine that it takes around 5 feedlot-raised, grain-fed cows to service a single NFL game!

Photo: David McLain/Bouncethemovie.com

D: What’s the longest-standing rivalry a ball has produced?

JF: That would have to be the “Uppies” vs. “Doonies” on the remote Scottish isle of Orkney. For the past 400 years or so, Orcadians in the town of Kirkwall have engaged in an annual game known as the Ba’. Depending on which side of the island you’re born on you’re either an Uppie or a Doonie for life. The Ba’ pits the two sides against each other in the largest scrum you’ve ever seen.

D: Do you think life on earth will evolve out of using a ball?

JF: What a frightening thought! No, I really don’t. The balls we play with today may be more aerodynamic and responsive but they are not that different than balls we were playing with hundreds of years ago. There’s a simple perfection to the ball that’s hard to improve on dramatically or replace outright with some 2.0 version. Look, I fully expect that virtual play will continue to compete for our time with physical play—and I envision the two melding in interesting ways, particularly in how we spectate. But I think as living, breathing, sentient beings we will continue to be drawn to the ball as an object that grounds us in the human experience in a profoundly gratifying way.