"The introduction of a new alpha predator can have dramatic effects, even causing cascades of extinction. This is not necessarily because the alpha predators overhunt or are even in the least bit maladaptive; this is simply the nature of alpha predators and how they relate in any given ecology. When humans came to Australia and the Americas, they were as harmless as wolves, lions, or any other big mammalian predator. Their presence caused cascades of changes throughout the ecosystem. Given that it was also a period of major climate change, a great number of species that were already under stress adapting to the new climate were tipped over the edge into extinction by the further ecological changes created by the adaptation of a new alpha predator. Our ancestors were hardly noble savages; but neither were they bloodthirsty killers bent on the destruction of all life on earth. They were animals, like any other."