8 Things You Never Knew About Dragonflies

4. Dragonflies Are All Eyes

If you look at a dragonfly’s head, you might notice one thing in particular—or, rather, 30,000 things in particular.

The area of an odonate’s head is composed primarily of its enormous compound eyes, which contain 30,000 facets, each bringing in information about the insect’s surroundings. Dragonflies have nearly 360-degree vision, with just one blind spot directly behind them. This extraordinary vision is one reason why they’re able to keep a watch on a single insect within a swarm and go after it while avoiding midair collisions with other insects in the swarm.

5. They Can Live Years Underwater

Dragonflies lay their eggs in water, and when the larvae hatch, they live underwater for up to two years. Actually, depending on the altitude and latitude, some species may stay in the larval state for up to six years.4 They’ll molt up to 17 times before surfacing and transforming into the dragonflies we see in the air.

They are specially adapted for the aquatic life in this stage, with the ability to snag prey at lightning speed. They’ll eat a large variety of food, including other insect larvae, tadpoles, fish, and yes, even other dragonfly larvae.

6. Some Lay Eggs in Saltwater

Relatively few insects inhabit the ocean, perhaps because they have trouble surviving in saltwater. That doesn’t seem to bother some dragonflies, however. Certain species, like the seaside dragonlet (Erythrodiplax berenicei) can even produce offspring in environments saltier than typical seawater.

The seaside dragonlet is a standout species because its habitat consists of salt marshes, mangroves, and saline lakes. It’s the only dragonfly species in North America (but not in the world) with a range that’s restricted to salty habitats.

7. Dragonflies Are Beneficial to People

Dragonflies help humans by controlling populations of pest insects, especially those that threaten us most, such as mosquitoes and biting flies. A single dragonfly can eat anywhere between 30 and hundreds of mosquitoes per day.

Dragonflies also inspire us to create new technology—from drones to artificial visual systems—because of their incredible flight skills and vision. The least we humans can do to return the favor is support the conservation of their habitats so they can continue on for another 300 million years.

8. They Can Be Admired in Sanctuaries Around the World