Cicadas pee a lot, particularly during warm days. And when thousands of cicadas are perched overhead on tree branches, their pee falls to the ground like a gentle rain shower.

Their pee is also called honeydew, and it’s loaded with sugar. It’s slightly sticky and gummy, so it’s wise to wear a hat when walking in the woods this month. But it’s harmless, just like the cicadas that squirt it out.

“It feels like when a rain just starts, and you get a small drop or two and say, ‘Is it starting to rain?'” Paula Shrewsbury, a professor of entomology at the University of Maryland, wrote in an email. “[I]nstead, now you say, ‘Is that cicada pee?’ So little specks of wet, and it never gets any stronger than that.”

It feels like when a rain just starts, and you get a small drop or two and say, ‘Is it starting to rain?’ [I]nstead, now you say, ‘Is that cicada pee?’ So little specks of wet, and it never gets any stronger than that.”
— Paula Shrewsbury,
professor of entomology at the University of Maryland

But why do cicadas pee frequently?

“As adults, cicadas are active on the hottest days because they can tap into the dilute, watery xylem fluid of deciduous trees,” wrote Daniel Gruner, also a professor in U-Md.’s entomology department. “Evaporation of moisture cools their bodies by as much as five to ten degrees, just as humans sweat and dogs pant, but an excess of fluids forces them to pee liberally.”

Thus, cicadas ingest tree fluids more for cooling than nutrition. Then they quickly pee it out.

While our cicadas pee in sprinkles, other species of cicadas can make it rain. Check out the videos below showing free-flowing pee produced by cicadas located in other parts of the world. No doubt, you will want to wear a hat or carry an umbrella when venturing into their territory.