Ocean quahog

A North Atlantic clam called the ocean quahog may live as long as 507 years, which edges out even the Greenland shark. It is an invertebrate, so the shark keeps the title for animals with a backbone.

The 507-year figure is a maximum reported for the species, not an average.

Context

The ocean quahog (Arctica islandica) is a thick-shelled clam found in the cool North Atlantic. Like a tree, it lays down a visible growth line in its shell each year, so scientists can count the lines to find its age and read past ocean conditions from them.

The 507-year record belongs to a clam nicknamed Ming, collected off the coast of Iceland in 2006. It was first reported as about 405 years old, then re-analysed with more careful counting and revised to 507, which means it began life around the year 1499. The clam died in the process of being studied, which is a reminder that the best ageing methods for animals without records are often destructive.

This is why the record is about invertebrates, not vertebrates. The Greenland shark has the longest confirmed lifespan among animals with a backbone, while the ocean quahog is the longest-lived animal of any kind that scientists have been able to date reliably.