Captain Planet and the Planeteers (1990) : 6x9

The Planeteers are climbing Mount Everest in the Himalayas when they follow a snow leopard and fall into a cavern where they encounter a Yetti among 12 extinct or endangered animals, all of whom can speak, and begin to judge not only the Planeteers, but the entire human race. They go back from the Ice Age and various other time periods where the animals were either hunted or had their habitats destroyed by humans resulting in their extinction or becoming endangered. This episode is used to educate both of the past, present, and future for the viewers it explains how we can have everything one day and lose everything later.