WASHINGTON — Most octopuses lead solitary lives. So scientists were startled to find thousands of octopus huddled together, protecting their eggs at the bottom of the ocean off the central California coast.

Now researchers may have solved the mystery of why these pearl octopus congregate: Heat seeping up from the base of an extinct underwater volcano helps their eggs hatch faster.

“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.

The octopus — about the size of a grapefruit — perched over their eggs laid on rocks heated by water seeping up from the sea floor.

“It was completely incredible — we suddenly saw thousands of pearly-colored octopus, all upside down, with their legs up in the air and moving around. They were pushing away potential predators and turning over their eggs,” for an even flow of water and oxygen, said National Oceanic and Atmospheric Administration marine biologist Andrew DeVogelaere, a study co-author.

Only the hazy shimmer of escaping hot water meeting the frigid sea alerted the researchers to the hydrothermal seep. But they still didn’t know exactly why the octopus had gathered there.

For three years, scientists monitored the site to understand the hatching cycle, recording both the developmental stage of eggs at 31 nests and the inevitable deaths of octopus moms.

“After the hatchlings come out of the nest and swim off immediately into the dark, the mothers, who never left their nest and never appeared to feed during nesting, soon die,” said James Barry, a biologist at the Monterey institute and co-author of the study.

The researchers found that eggs at this site hatch after about 21 months — far shorter than the four years or more it takes for other known deep-sea octopus eggs.

“Usually, colder water slows down metabolism and embryonic development and extends life span in the deep sea. But here in this spot, warmth appears to speed things up,” said Adi Khen, a marine biologist at the Scripps Institution of Oceanography, who was not involved in the study.

Mike Vecchione, a Smithsonian National Museum of Natural History zoologist who was not involved in the study, praised the researchers’ tenacity “to gather so much detailed data about such a remote location.”

Such octopus gardens “may be widespread and really important in the deep sea, and we just previously knew very little about them,” he said. “There’s still so much to discover in the deep sea.”

Uber raises minimum age for most California drivers to 25, says insurance costs too high

SAN FRANCISCO — Uber raised the minimum age requirement for most of its new drivers in California to 25 on Thursday, Aug. 24 under rules the company said are necessary because of the rising costs of commercial auto insurance in the state.

The new rule applies only to drivers signing up to transport passengers with Uber’s ride-hailing platform, and not for those delivering food with Uber Eats. Previously drivers as young as 19 could sign up.

Those under 25 who activated their accounts prior to Aug. 23 can continue to drive for Uber, the company said.

Insurance rates for Uber’s California drivers are significantly higher than for personal vehicles or taxi drivers, according to a company statement announcing the change.

“As a result of these lopsided requirements, personal injury attorneys have created a cottage industry specializing in suing rideshare platforms like ours, pushing Uber’s California state-mandated commercial insurance costs to rise by more than 65% in just two years,” the company said. “By increasing the age requirement for new drivers to 25, we hope to mitigate the growth of those costs.”

All 50 states require commercial insurance for drivers to earn money with a ride-hailing service. Uber maintains commercial auto insurance for drivers — including at least $1 million of liability coverage once a ride is accepted. Personal auto insurance typically doesn’t cover activity on ride-hailing apps.

The minimum age is already 25 for those driving for Lyft, Uber’s main competitor.

World Cup plans in Okinawa unaffected by North Korean spy satellite launch attempt

MANILA, Philippines — Plans for the start of the Basketball World Cup in Okinawa, Japan, were unaffected Thursday, Aug. 24, after a North Korean rocket launch prompted an alert ordering some residents to evacuate.

Press conferences and practices for the eight teams that are beginning World Cup play in Okinawa went on as scheduled. The tournament begins Aug. 25, also in the Philippines and Indonesia. There were no reports of damage.

“It was a little scary,” Slovenia star Luka Doncic of the Dallas Mavericks said when asked what it was like to experience the alert, which went out shortly before 4 a.m. local time.

“I didn’t sleep much,” he added.

Along with Slovenia, the other nations playing group-stage World Cup games in Okinawa starting Aug. 25 are Finland, Germany, Australia, Japan, Cape Verde, Georgia and Venezuela.

North Korea confirmed after the early morning launch Aug. 24 that it was an unsuccessful second attempt to launch a spy satellite. Japanese officials said parts of the rocket fell into the Yellow Sea, the East China Sea and the Pacific Ocean.

“It was crazy,” Doncic said.