They look like starfish that stretched out for yoga, with tiny round bodies and five long, whip-like arms. Meet the brittle stars, the lesser-known cousins of starfish, found everywhere from coral reefs to the darkest trenches more than 3,500 meters down. Quick, flexible, and able to regrow lost limbs, these creatures scuttle across the seafloor or wave their arms to catch drifting food.

In August 2025, researchers published a groundbreaking DNA study in Nature after examining nearly 2,700 brittle stars from museum collections. They discovered something astonishing: species separated by oceans are often closely related. From Iceland to Tasmania, these creatures are linked by ancient “superhighways” of deep-sea currents.

The secret lies in their larvae. While adult brittle stars stay rooted to the seafloor, their larvae can drift for weeks or even months on slow-moving currents. It works much like seeds or pollen in plants. The adults stay put, but their offspring travel, carried by ocean currents the way seeds drift on the wind. 

Over millions of years, this has spread brittle stars across vast distances, turning the ocean floor into a connected network rather than a patchwork of isolated habitats.