Scientists discover why thousands of octopuses huddle in a deep-sea crevice – video

A study of the biggest known congregation of breeding octopuses, about 20,000, has made discoveries as to why so many of the species gather there. A volcanic vent in the ocean bed off California provides warm water and nutrients to the brooding octopuses, and scientists from MBARI have found this helps shorten the time it takes for their eggs to hatch, increasing their chances of survival

• Discovered in the deep: an octopus's garden in the shade