The mysterious disappearance of Greenland’s medieval Norse society in the 15th century came after walruses were hunted almost to extinction, researchers have said.

Norse communities thrived for more than 400 years in the Arctic, hunting walruses for their tusks, a valuable medieval commodity.

But a mixture of overexploitation and economic pressure from a flood of elephant ivory into European markets in the 13th century contributed to their downfall, according to a study.

A team of researchers from the universities of Cambridge, Oslo and Trondheim examined pre-1400s walrus tusk artefacts from across Europe and found almost all of them came from walruses hunted in seas only accessible to Greenland Norse communities.

They also found later items were hunted from smaller animals – likely females and infants – signalling stocks were rapidly dwindling.

James Barrett from Cambridge University’s archaeology department said: “Norse Greenlanders needed to trade with Europe for iron and timber, and mainly had walrus products to export in exchange.

“Norse hunters were forced to venture deeper into the Arctic Circle for increasingly meagre ivory harvests.” As walrus populations declined, so did the Norse communities.

The authors of the study, published in the Quarternary Science Reviews journal, said there were likely to have been other factors that contributed to the eventual disappearance of Norse Greenlanders.

These include climate change as the northern hemisphere underwent a “little ice age”, and unsustainable farming techniques.

Bastiaan Star of Oslo University said: “If both the population and price of walrus started to tumble, it must have badly undermined the resilience of the settlements. Our study suggests the writing was on the wall.”