Cicadas are a group of fascinating insects found on every continent in the world, except Antarctica. 

One of the things that sets them apart from other insects is their…unusual life cycle.

Some species spend almost their entire lives underground. This stage, called the nymph stage, lasts either 13 or 17 years. 

The timing of the cycle remains a mystery to scientists, but they know it is associated with the temperature and soil conditions.

This year is the 17th year for one species native to Virginia, West Virginia, and North Carolina. 

When the cicadas transition from nymphs to mature adults, they emerge from the ground and begin to…well…scream. 

It’s a good-natured scream though. The alien-like wails are actually mating calls from male cicadas, used to attract emerging females. 

As many as 1.5 million cicadas will emerge per acre, according to entomologists at Virginia Tech.

“Communities and farms with large numbers of cicadas emerging at once may have a substantial noise issue,” Eric Day, an entomologist in Virginia Tech’s Department of Entomology, said in a statement. “Hopefully, any annoyance at the disturbance is tempered by just how infrequent — and amazing — this event is.”

The event has started already but is expected to hit its peak in the next couple of weeks. 

Cicadas are not dangerous to humans and the wailing will only last for 4-6 weeks, the span of the mature adult life of the insect.