Among the many things you should be thankful for this Thanksgiving are the humble pumpkin and the trusty squash. No, seriously.
A new study, carried out by researchers at Penn State and published today in Proceedings of the National Academy of Sciences, says the Thanksgiving staples we eat are distant survivors of ancient fruits that avoided extinction only because they were cultivated by humans.
Before humans even existed in the Americas, there were wild precursors to the genus Cucurbita—i.e., pumpkins, squash, and gourds—all over the place. In fact, mastodons, giant ground sloths, and gomphotheres—a huge elephant-like creatures with shovel-shaped jaws—enjoyed eating them like they were ancient Tic Tacs. The researchers have figured out that both the squash and the pumpkin evolved to have hard, tough rinds, and bitter flesh to prevent them from being devoured by smaller animals and into extinction.
But here's the thing: When humans arrived in the Americas between 13,500 and 14,500 years ago, these wild Cucurbita actually did go extinct. Overhunting and climate change, which wiped out the large mammals that dispersed the Cucurbita seeds, led to their swift demise.
So the wild Cucurbita species, once widespread in the Americas, was gone. What remains today are the progeny of domesticated cucurbita, dating from the beginning of human cultivation of these fruits about 10,000 years ago. Anthropologist Logan Kistler, the lead author of the study, says, "one of the common types of canned pumpkin that a lot of people in the US will be opening up for pies this season has no known wild counterpart [today]." In short, we were this close to losing pumpkins and squash all together!
Because the first domesticated cucurbitas were likely quite bitter—more like their wild counterparts—they were probably first used as tools or containers, Kistler told Popular Science. But once humans started using them and dispersing their seeds, their survival was ensured.
Domestication probably began in what is now Mexico and followed throughout North America. The authors say that early humans provided patchy landscapes, which mimicked the landscape pre-overhunting, and was just what the weedy cucurbita enjoyed, thereby allowing them to establish themselves throughout our homeland.
Phew. Imagine that: We almost lost the pumpkin and the squash in their seedy entireties. What would Thanksgiving be without these weird, distinctly American gourds? The pumpkin spice latte was nearly aborted before its very birth. Thankfully, our noble friends the pumpkin and the squash know all too well that the best way to avoid the ails of humanity is to be domesticated by them and offer up your sweet, supple flesh in tribute.