A bumblebee can survive underwater for a week while sleeping.

A lab error has revealed that hibernating bumblebees can survive for at least seven days even when completely submerged in water. This ability suggests that beleaguered insects are more resilient than previously thought.

Sabrina Rondeau I came across this discovery by chance while researching eastern bumblebees (St. impatiens) in a laboratory at the University of Guelph, Canada. One week, she was checking on the hibernating queen bees kept in a hibernation chamber, a tube filled with soil in the refrigerator, when moisture overflowed into the tube and four queens were submerged in the water. I noticed that I was sinking. “I was a little surprised,” she says. “I was sure the queens were dead.”

To everyone's surprise, after draining the water, the bees woke up unharmed. Rondeau had a hunch that undiscovered abilities were at work.

She systematically drowned 21 queens over seven days, and 17 of them, or 81%, survived the flood. “This is a very high survival rate, not much different than before. [hibernation survival] When there’s no water,” Rondeau says. This achievement is probably due to the fact that dormant bees reduce their metabolic rate. This means that bees require very little oxygen, which can be met by air stored within their bodies.

“Wow, the fact that you can submerge a land animal in water for a week and find that it's still alive is really amazing,” he says. Lars Chitka at Queen Mary University of London.

Male bees and worker bees die before the winter, but the queen bee endures the cold for up to eight months by hibernating, waking up in the spring to begin building a new nest. The number of queens that survive is directly related to future population growth.

These bees hibernate underground, so extreme weather can destroy their safe haven. “It's a pinch point in their life cycle,” he says Nigel Lane, Dr. Rondeau's supervisor at the University of Guelph, Canada. This is a problem because about a third of all bumblebee species are already in decline. Finding that they are physically adapted to survive potential flooding is “really, really good news,” he says.