While conservationists have managed to save a number of rare and precious creatures from going extinct, not all have been saved.
With Earth Day upon us, here's a look at 10 of the animals we've lost in the last century.
Heath hens, a prairie chicken subspecies, rapidly vanished from the East Coast mainland during the mid 1800s, but survived in a sanctuary in Martha's Vineyard, Massachusetts, until the last perished in 1932.
The thylacine, or Tasmanian tiger, was a dog-like marsupial with the head of a wolf. The shy Australian animals died after only a century of European settlement. Despite the world's last captive thylacine dying in 1936, the secretive animal wasn't declared extinct until 1986.
More recently in 2007 the Baiji dolphin , a rare river dolphin native to China, was presumed extinct. The last documented sighting of the baiji dolphin occurred in 2002.
And just in the last decade there have been many more animals that disappeared from the planet, despite efforts by scientists.
Look below for animals that extinct within the past century, including many within your own lifespan:
1. Baiji dolphin-Year declared extinct: 2007
2. Heath Hen-Year declared extinct: 1932
3. Thylacine, also known as 'Tasmanian wolf' or 'Tasmanian tiger'-Year declared extinct: 1986
4. Pinta tortoise-Year declared extinct: 2012
5. Golden toad-Year declared extinct: 1989
6. Caribbean monk seal-Year declared extinct: 2008
7. Caspian tiger-Year declared extinct: 1958 or 1970
8. Formosan clouded leopard-Year declared extinct: 2013
9. Pyrenean ibex-Year declared extinct: 2000
10. Toolache wallaby-Year declared extinct: 1937 or 1970's
Apr 22nd 2016 3:00AM