The Aquatic Neanderthal: They Could Swim and Dive for Clams

Over 100,000 years ago, a group of Neanderthals in Italy would winter in a cave by the seaside and dive as much as 4 meters deep to collect shells – but not for eating

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Grotta dei Cavalli
Grotta dei Cavalli, where Neanderthals also made tools from clamshellsCredit: Davide Mauro
Ruth Schuster
Ruth Schuster
Ruth Schuster
Ruth Schuster

Neanderthals could swim. Not only could they swim: They were diving possibly as much as 4 meters (13 feet) deep for live clams, in Italy at least, an international team of archaeologists reported in PLOS One on Wednesday.

Strangely, even though the Neanderthals on the Italian coast seemed to dote on mussels, they don’t seem to have been clamming for consumption. They were using the shells of a very specific species mainly, and perhaps solely, to make scraping tools, Paola Villa of the University of Colorado Boulder and colleagues report, based on reanalysis of findings made decades ago.

The paper is based on archaeological finds in a cave called Moscerini in Italy – one of only three sites in the world where strong evidence has been found of systematic use of shell scraper manufacture by Neanderthals.

The shell tools were found throughout multiple archaeological layers dating from 106,000 to 74,000 years ago.

Clamming in cold water

Moscerini was quite the Paleolithic palace: a large cave at the base of a cliff right on the coast. In fact, archaeological investigation of the grotto began 70 years ago, but then the cavern mouth got buried by road builders in the 1970s. The new paper is based on reanalysis of discoveries collected before the cave was choked off by falling boulders.

General morphology of retouched shell tools
General morphology of shell tools retouched by Neanderthals: note the finely chipped, sharpened edgesCredit: Villa et al., 2020

We know Neanderthals made stone tools, and toward their end some may have made tools so magnificently (Chatelperronian technique) that some have postulated they were actually made by incoming Homo sapiens. Shell-based toolmaking by Neanderthals is less well-known.

But make shell tools they did, if not commonly. In 1949, archaeologists found 171 of them in the cave at Moscerini. Another 136 were separately found at the cave of Cavallo, also in Italy, and much smaller numbers have been found in other Neanderthal haunts such as Kalamakia Cave in Greece.

The assumption had been that the Neanderthals just picked up shells on the beach, as people do. And they did. But the supposition that Neanderthals just collected dead mollusks on the beach is “incomplete,” claim Villa and her colleagues. Most of their shell-tools seem to have been made using deceased gastropods washed ashore. But a fifth to a quarter of the specimens found at the cave sites of Moscerini and Cavallo seem to have been collected alive off the seafloor.

All were made from a specific animal: the smooth clam, Callista chione. The shell edge was shaped with stone hammers.

The umbones of a bivalveCredit: Shellnut, elaboration by Haaretz

But why would they make these things in the first place, given their expertise at making stone tools that would last more or less forever, while shells are relatively fragile?

“The valves of Callista chione have a rather uniform low thickness from the edge up to the umbo,” Villa explains to Haaretz – referring to the highest, most prominent bulge of the bivalve’s half-shell.

“Experimental knapping indicates that you can retouch the clam edge two to three times and the edge remains thin and cutting (between 40 and 45 degrees),” she elaborates. “Flint tools when retouched change the edge thickness, because this is how flint flakes are done: thicker near the point of impact and thinner at the edge. Perhaps Neanderthals used shell tools when they needed a thin and sharp edge.”

Also, if the shell breaks, it can be retouched again and the edge will remain thin and sharp, she says.

The Neanderthals at Moscerini also collected pumice – a habit proven elsewhere in Italy (a cave in Liguria) by a previous study, the researchers say. The rough-textured volcanic rock were used to abrade, the archaeologists explained. The pumice likely was ejected by Campanian volcanoes erupting around 40 kilometers to the south of Moscerini. Being full of air bubbles, pumice floats on seawater and it must have washed up on the beach. Its use is unrelated to the swimming and clamming story, and from now we will ignore it while idly wondering if they used it for pedicures as people do to this day.

Neanderthals on the beach

As for the aquatic Neanderthal, there is a lot of evidence that they did not shy from water.

Separate studies have shown that Neanderthals fished for shells to eat and caught fish in shallow freshwater too. For example, a 2011 study reported on the earliest known consumption of shellfish in Spain, 150,000 years ago – thus debunking the notion that shellfish are a modern human passion. Neanderthals also bored holes into shellfish by the hinge (the umbones) and colored and decorated the mollusks too, 115,000 years ago in Spain.

Isotopic studies have indicated that Neanderthals preferred meat but also ate shellfish and fish, whether out of necessity or choice.

Further supporting the theory of aquatically competent Neanderthals: Last year, Erik Trinkaus of Washington University in St. Louis reported evidence of “surfer’s ear” in Neanderthal skulls – abnormal bony growths in the ear canal that are relatively prevalent among humans who swim in cold water. Presumably the Neanderthals weren’t surfing – but for that painful syndrome to develop, it’s possible they swam for fun as some of us do today, even in icy water (Polar Bear Club, looking at you, uncomprehendingly).

Callista chione clams (upper left) next to a Microchirus ocellatus sole
Callista chione clams (upper left) next to a sole (center bottom)Credit: Stefano Guerrieri / Etrusko25

Interestingly, in the latest Upper Paleolithic Neanderthal communities, that ear problem seems to have become less prevalent even though signs of marine resource exploitation abound. Maybe they perfected shallow-cold-water fishing techniques and could, for instance, spear a fish rather than dive for it.

When rocks run short?

The swimming Neanderthal is also plausible in the sense that almost all mammals can swim. Doggies revel in water sports. If a cat falls into the water, it can swim. Given their druthers, most cats would not. Nor would apes: they apparently see no reason to immerse themselves, but if necessary, they can survive the plunge. Experts in mammalian aquatic locomotion have singled out, of all things, the hippo as a non-swimmer – though it walks on the river bottom, giving observers the wrong impression.

So maybe Neanderthals were like us: able to swim, once we master the knack, and dredge clams from the seafloor.

No Neanderthal skeletons were found in the two Italian caves. However, the shellfish evidence predates the known arrival of anatomically modern humans to the area, Villa explains to Haaretz (though recent evidence suggests that modern-type Homo sapiens may have migrated to Europe much earlier than is presently proven).

“The fact they were exploiting marine resources was something that was known,” she says. “But until recently, no one really paid much attention to it.”

Fine, they ate fish and shellfish. But how do the archaeologists deduce that the Neanderthals of Italy dived as deep as 2 to 4 meters for live clams and didn’t just beachcomb?

For one: Studying the shell tools using advanced techniques, the team noticed that about three-quarters of the shell tools had slightly abraded exteriors and were opaque, as if sanded down over time. These, Villa and the team concluded, had indeed washed up on the beach and been picked up. The rest were bigger and had a shiny, smooth exterior. Based on their pristine state and the state of encrustation by marine life, the archaeologists feel they had to have been plucked directly from the seafloor, alive.

For two: Their beloved mussels can live in tightly clustered colonies at a depth of about a meter. The Neanderthals just had to wait for the Mediterranean tide to go out, wade, and bend over to pluck the animals from the rocks to which they adhere, Villa explains.

So mussels are clearly visible. Clams are not: they burrow in the sandy seafloor.

A clam showing its bits: The syphon is the protuberance on the right
A clam showing its bits: The syphon is the protuberance on the rightCredit: Allen Lew

“Because they burrow, they are often visible only by their syphon, which protrudes above the sediment since they need to feed, excrete and reproduce. The syphon indicates the presence of a clam,” Villa explains. “The simplest way [to collect them] is to put your head under water and gather them by scooping sand with your hand. Clams now are collected by dredging, and in some places by scuba diving. But Neanderthals had no scuba diving equipment, so they could go to no more than 1 to 4 meters.”

Mysteriously, the shell tools were not distributed evenly throughout the Neanderthal-associated sequence. Where shell tools were common, stone tools were not – leading to thoughts that perhaps shell tools were made when appropriate stone was harder to come by. The archaeologists also detected evidence of stone tool recycling, which could attest to scarcity of the raw material, frugality, convenience or something else.

The bottom line is that the team suspects the Neanderthals – at least in one of their phases at the cave – would only move to the cave in the winter, to fish for shells. They would bring their pet stone tools with them. Then they would leave. “Simply put, the cave has a long stratigraphic sequence but the human occupations were of short duration,” the researchers posit.

So we have concluded that Neanderthals were likely swimming and diving to collect clams, from which they made scrapers in winter. But given that said clams were edible, wouldn’t we assume they’d eat them and not only mussels and other seafood?

Though these Neanderthals clearly had fire, the researchers did not find evidence of clambakes. “The Neanderthals may have eaten the animals from Callista chione shells. There is no sure evidence in favor or against,” Villa shrugs by email. “All shell tools at Moscerini and most other sites are exclusively made from Callista chione and there are always much fewer shells than of mussels.”

Maybe raw clam was indeed a rare delicacy in which they delighted. But let’s face it, the mussels were a lot easier to catch.