Notre Dame's unseen residents — 180,000 bees — stayed put on the roof of the iconic cathedral as it burned on Monday. Their beekeeper was worried they wouldn't make it, but on Thursday, he was relieved to find out the bees survived the blaze.

"An ounce of hope!" beekeeper Nicolas Geant wrote on Instagram, sharing a drone photo of Notre Dame's scorched roof. "Drone photos show that the 3 beehives are still in place and seem to be intact!"

At the time, Geant, who tends to the hives on Notre Dame's roof, didn't know if the bees were still alive. "Smoke, heat, water... we'll see if our courageous bees are still with us as soon as we have access to the location, which will likely take a long time."

But just a day later, Geant already had an update. "The bees of the Notre-Dame Cathedral are still alive! Those responsible for the site have confirmed!" He shared a photo of some bees huddling in a crevice of a gargoyle sculpture and added the hashtag "#miracle."

Geant explained how the bees managed to survive in an interview with The Associated Press. "Instead of killing them, the CO2 (from smoke) makes them drunk, puts them to sleep," he said. The beekeeper said it was a "big day" and he was relieved to learn the bees went into survival mode during the devastating fire.

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"When bees sense fire, they gorge themselves on honey and stay to protect their queen, who doesn't move," Geant said. "I saw how big the flames were, so I immediately thought it was going to kill the bees. Even though they were 30 meters (about 100 feet) lower than the top roof, the wax in the hives melts at 63 degrees Celsius (145.4 Fahrenheit)."

Bees don't have lungs, so they can't die from smoke inhalation. In fact, smoke is often used by beekeepers to sedate a bee colony when they need to get inside their hives.

However, excessive heat can kill them, and melt the wax that protects their hives. Unlike other bees, European bees don't abandon their nests during danger, the AP reports. So, they took the risk, hunkered down, and managed to survive.

Three hives were installed on the roof of Notre Dame in 2013, as part of a citywide initiative to boost declining bee numbers in Paris, the AP reports. Geant has overseen the bees since the hives were installed, and he gives updates on his Instagram page, which has gained more popularity with the news of the tenacious bees.