THE EXTINCTION OF ANIMALS (EXTINGUISHED AND TO BE EXTINGUISHED) Extinctions happen when a species dies out from cataclysmic events, evolutionary problems, or human interference. The truth is, scientists don’t know how many species of plants, animals, fungi, and bacteria exist on Earth. The most recent estimate put that number at 2 billion , and that will most likely change at some point. One thing we do know: The western black rhinoceros, the Tasmanian tiger, and the woolly mammoth are among the creatures whose populations at one point dwindled to zero, and it’s possible that species extinction is happening a thousand times more quickly because of humans . The last living Rabb's fringe-limbed tree frog died in 2016 at Atlanta Zoo. The now-extinct Panamanian frog species was discovered in the wild in 2005, and just two years later no more of the frogs could be found. Extinction happens when environmental factors or evolutionary probl