The approximately 180,000 bees were apparently intoxicated by the smoke of the flames, Notre Dame beekeeper Nicolas Geant told The Associated Press Friday.
“It's a big day. I am so relieved,” he said. “I saw satellite photos that showed the three hives didn't burn.”
“Instead of killing them, the CO2 (from smoke) makes them drunk, puts them to sleep,” he explained.
Beeopic, a Paris-based urban beekeeping company, posted about the surviving bees on its Instagram page Thursday.
“Our bees at Notre Dame Cathedral are still alive,” the post said in French. “Confirmation from the site managers!! Our Lady’s bees are still alive!”
The day before, the company had posted a satellite picture of the hives that were still intact on the sacristy roof but said the fate of the bees was unknown at the time.
The three beehives were installed in 2013 on the roof of the sacristy at the south end of the cathedral. The sacristy, which is made of stone, sits lower than the cathedral’s main roof — made of wood — which burned and collapsed along with the spire during the fire on Monday.
Even though smoke is harmless to bees — and is often used by beekeepers to sedate the colony to access their hives — excessive heat can kill them by melting the wax that protects the hives. European bees, unlike some other species, stay with their colony in times of danger.
“When bees sense fire, they gorge themselves on honey and stay to protect their queen, who doesn't move,” Geant explained.
“I saw how big the flames were, so I immediately thought it was going to kill the bees. Even though they were 30 meters [nearly 100 feet] lower than the top roof, the wax in the hives melts at 63 degrees Celsius [145.4 Fahrenheit],” he added.
However, when Notre Dame officials got to the roof, they found the bees buzzing in and out of their hives.
“I wouldn't call it a miracle, but I'm very, very happy,” Geant said.
The hives, which produce about 165 pounds of honey every year, were added to the sacristy as part of a Paris-wide initiative to boost declining bee numbers. Hives were also introduced above Paris’ gilded Opera.
Investigators in Paris said Thursday they believe an electrical short-circuit is most likely the cause behind the massive fire at the cathedral, though an investigation is ongoing.
Fox News’ Barnini Chakraborty and The Associated Press contributed to this report.