The world’s largest known group of octopuses can be found in a place called the Octopus Garden. It’s tucked against a seafloor hill off the coast of California. Here, thousands of pearl octopuses (Muusoctopus robustus) gather to breed. Scientists have wondered for years what drew so many pearl octopuses to this spot. Now, underwater cameras and other tools have revealed the answer. Researchers shared the work August 23 in Science Advances.

JOANNA WENDEL