Octopuses are usually solitary. So it came as a surprise when scientists found an octopus nesting ground off the California coast with thousands of mothers tending nests.
According to The Columbian researchers believe they know why the pearl octopus mothers congregate: warm water. The water seeping up from an undersea volcano helps the eggs hatch faster. The newspaper is based in Vancouver, Washington. The octopus nesting ground is deep in the waters off California.

The pearl octopus is about the size of a grapefruit and inhabits deep water. At 10,500 feet the water is about 35 degrees.
Th Columbian said:
“There are clear advantages of basically sitting in this natural hot tub,” said Janet Voight, an octopus biologist at the Field Museum of Natural History in Chicago and co-author of the study, which was published Wednesday in Science Advances.
The researchers calculated that the heated nest location more than halved the time it took for eggs laid there to hatch — reducing the risk of being munched by snails, shrimp and other predators.
The nesting site, which the scientists dubbed an “octopus garden,” was first discovered in 2018 by researchers from the Monterey Bay National Marine Sanctuary and other institutions. The team used an underwater remote vehicle to film the throng of nearly 6,000 octopus nesting 2 miles deep.” (My links)

Schmidt Ocean Institute says Voight has been studying octopuses for more than 40 years and is interested in all areas of their lives.

The octopus has been in the news recently for several reasons. First, they apparently may help in the fight against forms of cancer. The anti-cancer agent may be part of octopus ink.
According to New Scientist the compound in question is ozopromide. The compound appears to kill cancer cells but leave other cells alive. The compound is found in the common octopus (Octopus vulgaris). Research is being conducted by Martin Samuel Hernandez-Zazueta. He is a professor at the University of Sonora. Mexico. He and his team have synthetically manufactured the compound and are studying its anti-cancer properties.
Octopuses (or octopi) also dream in a manner similar to humans. Recent research also suggests they have nightmares.