animals that have become extinct due to natural selection?
['Sabre-toothed Cat. Often called Sabre-toothed Tigers or Sabre-toothed Lions, they existed 55 million to 11,700 years ago.', 'Woolly Mammoth. ... ', 'Dodo. ... ', 'Great Auk. ... ', 'Stellers Sea Cow. ... ', 'Tasmanian Tiger. ... ', 'Passenger Pigeon. ... ', 'Pyrenean Ibex. ... ']