NEW YORK, NY.- A number of cities vie for the unofficial title of “seafood capital of the world,” and Lisbon has a good claim. The city, Portugal’s coastal capital, is famous for its salted cod, sardines and stuffed brown crab. A study published Tuesday in the journal Frontiers in Environmental Archaeology reveals that these brown crabs have been on the menu for a long time. In a cave less than 20 miles from Lisbon, researchers discovered charred remnants of shells and claws: evidence that Neanderthals were cooking and eating crab 90,000 years ago.

The cave site, Gruta da Figueira Brava, was about 1 mile from the coast when Neanderthals lived there. It contained multiple chambers, including an open “porch” living area, probably large enough to accommodate at least an extended family. Rising sea levels slowly brought the Atlantic to the cave door.

Reaching Gruta da Figueira Brava today involves a climb down a craggy cliff face overlooking the sea. “It was a bit adventurous,” said Mariana Nabais, a postdoctoral researcher at the Catalan Institute of Human Paleoecology and Social Evolution and an author of the study. “In a way, it’s good that it’s hard to get there, because that’s what allowed it to preserve such incredible, incredible finds.”

During excavations, she and her team brought sediments from the cave back to their field lab on the hilltop so they could be studied, but Nabais and her colleagues recognized some bits of debris right away.

“You can immediately identify them on site as being crab claws, especially in Portugal, because we have a tradition of eating crabs a lot,” she said. “It was a big surprise, especially because when we were digging there, we still didn’t have that idea of Neanderthals actively eating shellfish.”

The researchers ultimately found 635 bits of crab shells, representing a bare minimum of 33 individuals, along with remnants of barnacles and sea urchins. A vast majority of the crabs were the same species of brown crab served with roe and mustard in Lisbon today. Based on the size of the claws, most of the specimens were larger than average, each likely yielding around 7 ounces of meat.

The shells lacked telltale signs of being eaten by other animals, like tooth marks or shattering patterns from being dropped on rocks by birds. Instead, some of the shells were charred and blackened: a sign that they had been roasted.

Nabais said that the discovery, which follows a 2020 study in Science detailing the variety of animal remnants found in the cave, including birds and tortoises, is more refutation for the traditional view of Neanderthals, humanity’s closest relatives, as dullards compared with modern humans.

“We’ve always seen Neanderthals as like these brute cousins,” she said. One argument against Neanderthal intelligence was the idea that they were capable of scavenging or hunting only large prey like elephants, while cleverer humans adopted a broader diet including fatty-acid-rich fish that promoted brain development.

“What we see nowadays, more and more, especially in the Mediterranean area, is that these Neanderthals that lived here were actually eating small prey,” Nabais said. “Now, we know they were eating shellfish as well, which was something that people thought that they wouldn’t be capable of because they were a bit dumb.”

Fred H. Smith, a professor emeritus of anthropology and biological sciences at Illinois State University who was not involved with the study, praised the researchers’ thoroughness and agreed with their conclusions about Neanderthal versatility and intelligence.

“Twenty, 30 years ago, basically, it was thought that Neanderthals were not capable, or at least not taking advantage of, using these resources,” he said. “So, we’ve come a long way.”

This article originally appeared in The New York Times.