In Attenboroughs Ark, Sir David explains why these animals are so important, and highlights the ingenious work of biologists across the world who are helping to keep them alive.
His top 10 includes Darwins frog - the only frog in the world where the male gives birth to its young. There is also the olm - a salamander that can live to a hundred. Theres also the Sumatran rhino - the smallest and most threatened species of rhino. David tells the story of the first-ever Sumatran rhino to be born in captivity in Asia. After years of failed attempts, a male Sumatran rhino was born at Cincinnati Zoo. He was sent to Sumatra, where he was matched up with a native female. The result was a historic baby, which gives hope to the rest of the species. In Jersey, David introduces his favourite monkey - the mischievous black lion tamarin - which is being bred successfully at Durrell Wildlife Park.