Vikings settled in Greenland and grew up to 6,000 over the centuries, but they came to an unclear end in the 16th century, leaving the island country vacant for 100 years. New research suggests one reason for this decline was the bottoming out of their economy, meaning the world stopped asking for walrus ivory.

Matthew Gabriele writes, “Specifically, the Greenland settlements built their economy around the trade in walrus tusks (ivory) and supplied maybe up to 80% of the ivory items for most of Europe between the 12th-15th centuries.”

Some thought the ivory used in medieval luxury items was from elephants, but this research argues that elephant ivory was rare and expensive. The more affordable ivory came from walruses. But this market dried up when the Black Death killed 60% of Europe.

Gabriele also writes about research into the collapse of the Mayan civilization. A paper published in Science this month says a 200-year drought crushed the Mayan empire, to which Gabriele says it’s more complicated than that and we already that part.

“Most likely, it was a number of factors that caused the decline, with the environment being only 1 of them. And this is what can happen when STEM fields ignore the humanities and social sciences. They too often ‘rediscover’ something that other scholars have known for some time.”

We all have our blind spots, don’t we?