Conservation has helped save many species from going extinct.
In 1981, there were only eight black-footed ferrets left in the world. Conservation has since raised the population to almost 10,000.
But many species are still in danger.
Take a look at some animals who have been saved from extinction, and some of those who still face the threat.
(Photos: 1 John Cancalosi; 2 Shattil & Rozinski; 3 David Fleetham; 4 Eric Baccega; 5 Mark Cardwadine; 6 Warwick Sloss; 7 David Tipling; 8 Juan Carlos Munoz; 9 Anup Shah; 10 Doug Perrine; Previous Page: Nick Garbutt; All Photos: naturepl.com / NaturePL)