The word 'unnatural' is often used to describe what's considered weird or unusual. But is anything weirder than nature? Biology abounds with creatures that change shape, change sex, change locations and in some cases cause other creatures to do these things.
It's a strange, marvelous world out there. On the following pages are gathered some of life's oddest, most extraordinary journeys.
Above:A Long Wait
Everyone's wondered what it would be like to step outside time for a while, to disappear one day and return, years later, to the same spot in a changed world. That's what cicadas of the Magicada genus have evolved to do.
The two Magicada species are known as 13-year and 17-year cicadas, the latter of which will in coming weeks emerge from soils along the eastern United States coast. In keeping with their name, they last visited 17 years ago, when they hatched from eggs laid on trees and plants and burrowed into the soil below.
Since then they've lived underground, drinking tree sap and slowly assuming adult form. After emerging, they'll live for just one more month, devoting their final days to finding mates. In a few months, the next generation will hatch and begin the cycle anew.
Except for their 13-year cousins, it's a life cycle unprecedented in the natural world. Scientists think it evolved as a defense mechanism: The time lag makes it difficult for predators to specialize in eating them, and when they do emerge, their overwhelming numbers make any losses insignifcant.
Image: Dan Century/Flickr/Cicadamania.com