Animal · United States, Canada
Periodical cicada
Magicicada septendecim — the name this animal has in the language scientists everywhere share.
The periodical cicada spends seventeen years underground as a young insect and then climbs into the light for only a few weeks. When a brood comes out, millions appear at once and the woods fill with a shrill chorus.
Picture credit: peterwchen (CC BY 4.0) · Wikimedia Commons
Where does the periodical cicada live?
Home: Broadleaf woods and tree-lined streets of eastern America.
In the wild it lives in these countries: the United States, Canada.
Conservation status from the IUCN: close to being at risk.
The short profile
Fully grown: 2.4-3.3 cm long, with red eyes and orange wing veins. On the menu: plants.
The story behind it
A periodical cicada starts life as an egg tucked into a thin twig. The young insect drops to the ground, digs itself in and spends the next seventeen years sucking watery sap from tree roots, well below the frost. Then, in one single spring, a whole generation reaches the same number: the soil opens, the nymphs climb the nearest trunk, split their brown skins and leave the empty shells clinging to the bark. The new adults have red eyes and orange wing veins, and the males sing together so loudly that a chorus can reach about 100 decibels. Six weeks later the adults are gone, the eggs are back in the twigs and the wood is quiet for another seventeen years. Scientists think the odd numbers thirteen and seventeen help, because few hunters can match a cycle that long.
Find it on the globe
Periodical cicada is there as a tiny animated figure that breathes and looks around. From far away the planet is only a blue ball; detail arrives as you zoom in, and this one appears once you are close enough. Open it on the globe.
It sits at its real coordinates, not near them — the same numbers listed in the facts above. Switch off the layer for this kind of place and it disappears again; the buttons for that are down the right-hand edge.
Questions children ask
Why do cicadas come out only every 17 years?
All the young insects of one brood keep the same long count underground and come up together. Scientists think a cycle of thirteen or seventeen years is hard for hungry hunters to match, and coming out all at once means too many cicadas to eat.
Are periodical cicadas dangerous?
No. They do not bite or sting and they carry no poison; their mouth is a straw made for plant sap. They can be very loud and they leave thin cuts in young twigs where the eggs go.
How loud is a cicada chorus?
Close to the trees a chorus can reach about 100 decibels, roughly as loud as a passing motorbike. Only the males sing, using a pair of ribbed plates that they click many times a second.
Where these numbers come from
Every figure on this page was checked against public reference sources before publication. Where sources genuinely disagree, the text says so.
Last checked: