Save the Gourds

A new study argues that they would have gone extinct if humans hadn’t intervened.

Brian Snyder / Reuters

I don’t remember who first taught me about gourding, but I do know this much: If you want a game that gets you in the mood for decorative-gourd season, well, this is it, people.

The gist: Hide a gourd someplace, wait for your friend to find it, and then—at the moment of discovery—get up in their face with some variation of, “Man, you just got gourded.”

A flash of bright orange when you unzip your bag—you, my friend, have been gourded. What’s that weird lump under your pillow? Wouldn’t you know, gourded again. Sit down at your desk chair without looking, only to screech and leap back up? Ouch. Mistake. And also, gourded. It’s like that Smirnoff Ice game the kids were so crazy about a few years ago, but with fewer nasty beverages and more appreciation for the bounty of autumn.

But none of this seasonal delight would have been possible if not for the ingenuity of our ancestors, who domesticated gourds and, in the process, saved them from likely extinction. In a study published today in the Proceedings of the National Academy of Sciences, a team of biologists argued that most members of the plant genus Cucurbita—a group that includes gourds, pumpkins, and squashes—has survived the past several millennia only because of human intervention.

Tens of thousands of years ago, wild Cucurbita had it pretty easy: Get eaten by a mastodon or some other large mammal, wait for said mammal to poop out the seeds, grow, repeat. But after the mass extinction of many of these larger animals around 10,000 years ago, the researchers argue, the plants were left without an effective method of dispersing themselves, as smaller animals wouldn't touch them.

“These squashes in their wild form are unbelievably bitter. They’re really, really unpalatable to humans, and to most smallish mammals and most medium-sized mammals,” said Logan Kistler, a biology research fellow at the University of Warwick in the U.K. and the study’s lead author. “But we know, because mastodons were dispersing these, that they weren’t bothered by these very bitter compounds.”

To confirm their hypothesis, the researchers analyzed the genomes of 46 mammals from mice on up to elephants. In general, the smaller the species, the greater the number of genes it had for bitter-taste receptors. At the same time, they also looked at the genomes of 91 different samples of Cucurbita—42 from domesticated varieties, 30 wild, and 19 preserved ancient specimens—to trace when the older, wild versions were domesticated into their current, less-bitter incarnations. The process began around 10,000 years ago, they discovered, or roughly around the time that the squash-eating megafauna began to die off.

(Many experts believe that mastodons went extinct as a result of human hunting, in which case, we also imperiled the gourds before we saved them. But either way, they're still here.)

“Vegetative changes following the megafaunal extinctions likely crowded out [Cucurbita’s] disturbed-ground niche,” the study authors wrote. “Thus, anthropogenic landscapes provided favorable growth habitats and willing dispersal partners in the wake of ecological upheaval.” In layman’s terms, this means humans saved the gourds. So go leave a pumpkin on someone’s chair, and wait patiently. You owe your ancestors that much.