The last of their kind
Fossils of extinct creatures elicit daydreams — seeing dinosaurs walk the Earth, watching the first birds take flight or observing a trilobite scurry through a tide pool.
Other than the remote hope of cloning extinct animals, these ponderings are reserved for the imagination. Extinction is the reason we should cherish the creatures that still roam the planet, the ones we still have a chance to experience. This is especially true when it comes to creatures teetering on the brink of extinction.
With this in mind, we present the world's rarest animals — species with fewer than 10 confirmed individuals left alive, including the northern white rhinoceros (pictured).
Editor's note: This slideshow has been updated since it was originally published in February 2013.