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Despite how resilient sharks may seem, though, they may not be able to dodge the fate of the dodo or the passenger pigeon.

In the 1800s, the sky would routinely grow dark when large numbers of the now-extinct passenger pigeon passed through this popular roosting area in northwestern, Pennsylvania.

The passenger pigeon, once the most abundant bird in North America—numbering in the billions—disappeared from the skies in just a few decades because so many people hunted them for sport.

The most vivid accounts of squirrel irruptions date to a time when old growth forests had yet to be logged, when bison roamed the West and flocks of passenger pigeons darkened the skies.

In moving those acorns, jays, certain mammals and probably the extinct passenger pigeon helped oaks regain their northern range after the glaciers of the last ice age displaced them.