In April of 2007, Bruce Robison sent a submersible into a huge underwater canyon in California’s Monterey Bay. At the canyon’s base, 1400 metres below the surface, he spotted a lone female octopus—Graneledone boreopacifica—crawling towards a rocky slope.

The team sent the sub to the same site 38 days later and found the same female, easily recognisable through her distinctive scars. She had crawled up the slope itself and was guarding a group of 160 small, milky teardrops cemented to the rock. They were eggs.

For many a female octopus, laying eggs marks the beginning of the end. She needs to cover them and defend them against would-be predators. She needs to gently waft currents over them so