Paleo peach pits: Was the sweet, juicy fruit in China way before humans?
Scientists found 2.5-million-year-old peach pits in southwest China, and they're remarkably similar to those found at the center of today's fleshy fruit.
Courtesy of Rebecca Wilf
Before humans trekked across Eurasia to modern-day China, a familiar fruit was already there.
When ancient humans arrived in Asia, they may have experienced what could be described as one of life’s simple pleasures: biting into a sweet peach on a hot summer day, the juice running down your chin.
Peaches may have grown in China for millions of years. And the proof is in the pits, according to new research published Nov. 26 in the journal Scientific Reports.
Road construction unearthed fossilized peach pits that scientists dated to over 2.5 million years ago. And these fossilized pits are surprisingly similar to modern peach pits.
Like today’s peach pits, the prehistoric pits have an oval shape and deep grooves cut through the fossilized pit.
But the ancient peaches were likely smaller than today’s fruits. The scientists estimate these peaches grew to about 2 inches across.
"If you imagine the smallest commercial peach today, that's what these would look like," study co-author Peter Wilf said in a news release.
Despite its small size, the prehistoric peach was likely delectable.
Dr. Wilf said, "It's something that would have had a fleshy, edible fruit around it. It must have been delicious."
Today, peach trees are domesticated. Humans plant the trees, make sure the flowers are pollinated and reap the fruits of such labor in juicy peaches.
But, according to this research, that may have only served to enhance the fleshy fruit.
"Is the peach we see today something that resulted from artificial breeding under agriculture since prehistory, or did it evolve under natural selection? The answer is really both," said Wilf.
When humans arrived on the scene, they likely figured out how to make new varieties of the fruit and bigger peaches with more flesh. Then, they would have facilitated the spread of peaches across the region and beyond.
Before modern humans showed up, animals, and perhaps early hominids, likely dispersed the wild peaches. By snacking on the sweet fruit, the animals would have spread the seeds, either by carrying the peaches and their pits elsewhere before munching, or through their feces.
China has been named as the home of the first peaches before. Scientists found peach pits in the Yangzi River valley dating as far back as 8,000 years ago. In their paper, published last year, the researchers point to evidence in those pits that domestication occurred in China.
Before this new paper, that was the oldest evidence of peaches in China. Ancient wild peaches had not been reported until now, pushing peaches’ presence in China back millions of years.
"The peach was a witness to the human colonization of China," Wilf said. "It was there before humans, and through history we adapted to it and it to us."
Study lead author Tao Su found the fossilized peach pits near his home in Kunming. Road construction had exposed rock, and the pits, dating to the late Pliocene.
At first the scientists were skeptical that the peach pits were so old. Perhaps the pits were simply modern contamination, such as the remnants of a construction worker’s snack. But radiocarbon dating placed the pits as older than 50,000 years, the limit of that dating method, and other tests determined the fossils are more than 2.5 million years old.