Species now largely vanished from the North Atlantic Ocean once calved and migrated in the Mediterranean Sea.

Ancient whale bones show that grey and right whales once plied the Mediterranean Sea — and might have fuelled a Roman whaling industry.

Long ago the eastern North Atlantic Ocean harboured both grey whales (Eschrichtius robustus) and right whales (Eubalaena glacialis), but whaling helped eradicate them from the region. It is not known whether the species also ventured into the Mediterranean, which is connected to the Atlantic by the Strait of Gibraltar.

To probe the animals’ history, Ana Rodrigues at the National Centre for Scientific Research in Montpellier, France, and her colleagues analysed protein and DNA in bone fragments excavated from Roman archaeological sites near Gibraltar. The team identified right and grey whales as the sources of several of the fragments, which suggests that the Mediterranean served as a calving ground for both species some 2,000 years ago.

At least 200 fish-processing plants dotted the area around Gibraltar during Roman times. Such facilities may have processed whale meat as well as fish, the authors say.