Some of the French volunteers who spent 40 days in a cave for science already want to go back, team leader says

• 15 French volunteers emerged from a cave last month after spending 40 days with no external contact.
• The aim was to see how people behaved with no cues letting them know the time.
• Some of the volunteers loved it so much they would want to go back, the team's leader told Insider.
• See more stories on Insider's business page.

Some of the volunteers who lived in a cave for 40 days for science were disappointed when the experiment was over and would love to go back, the team's leader told Insider.

The group of 15 men and women emerged from the Lombrives cave in the south of France on April 24.

They had spent 40 days underground without access to clocks or sunlight. The aim was to test the effects of living as a group outside of time.

At least three could happily go back, Christian Clot, team leader on this project, told Insider in a recent interview.

The group of volunteers was shocked to hear when the 40-day experiment was over. Until that moment nobody could be sure how long they had been underground, and most guessed that they still had 10 days to go, Clot said.

"We couldn't accept it and we couldn't understand it," he said.

The experiment led to "thousands" of data points that are being analysed by scientists and are expected to be published in a few months, according to Clot.

But the group has a "hard time" dealing with the end of the process, Clot said.

"And at least three people still now can't accept it. And they want to go back to the cave," Clot said.

The rest of the team are happy to be outside, he said. "But I must say it's hard. For me, mostly because since I'm out, my calendar is completely full."

"I sometimes think: Wow! it was so easy in the cave."

Going back in the cave for a longer time is possible, he said. "I would like to try a much longer. Maybe in a few months, I will try."