Whale bones dating to 20,000 years ago found at sites around Spain could be the earliest evidence that ancient humans used whale bones to make tools, according to a new study.

The findings, presented in a paper published in Nature Communications, are based on analysis of 83 bone tools and another 90 bones. The results show that a portion of the bones belonged to at least 5 different species of whale.

Sperm, fin, blue, grey, and right and/or bowhead whale bones were uncovered at the sites.

Today, many whale species are under threat of extinction in large part due to their use as a food resource, as well as for their oil, bone and baleen by humans for millennia. They have been a key part of subsistence for coastal human groups going back to hunter-gatherer and Neolithic eras.

Ancient humans would have acquired whale parts by “scavenging freshly beached animals, opportunistic killing and organised whaling,” the authors write.

“However, reconstructing the beginning of whale utilisation is challenging because prehistoric coastal sites are an especially fragile part of the archaeological record, many of them having been lost to marine erosion or flooded by the last marine transgressions,” they continue.

“In most cases, the only available evidence is indirect, in the form of materials of coastal origin transported by people into inland sites.”

Excavations mostly done in the last 10 years shows whale use by ancient humans 14,000 to 20,000 years ago. This includes whale barnacles at inland sites which suggesting transport of whale skin, blubber and meat.

The team used ZooMS, or Zooarchaeology by Mass Spectrometry, to identify proteins in the bone and, therefore, the species it belongs to.

Excavations in 2022 in the Basque cave of Isturitz, France, where several dozen whale bone objects were discovered. Credit: Jean-Marc Pétillon, Christian Normand.

The 83 bone tools were excavated at sites around the Bay of Biscay which lines the coast where northern Spain and southern France meet. Of these, 71 were identified as whale bones. The other 90 bones were found at Santa Catalina Cave in Spain’s northern Basque Country. 60 of these were from whale species.

Non-whale bones belonged to large terrestrial mammals such as mammoth, rhinoceros, reindeer and horse relatives. One bone belonged to a porpoise, either the harbour porpoise or Dall’s porpoise.

Fragment of a Fin Whale vertebra from the Basque site of Santa Catalina, Spain, around 15,500 to 15,000 years ago. Credit: Jean-Marc Pétillon, Eduardo Berganza.

Sperm, fin, blue, right and bowhead whales are found in the Bay of Biscay to this day. But modern grey whales are mostly limited to the northern Pacific and Arctic Oceans.

Chemical analysis of the bones suggests that the feeding habits of the ancient whales were slightly different than today. The chemical signature may be the result of ancient whales tending to feed on animals higher on the food chain, or in cooler waters.