"I once wrote an essay on 'Nature red in tooth and claw' for a college entrance exam. I imgine that it was liberally based on fiction or at least some half-baked ideas from inaccurate memories of zoology lessons. The phrase comes from Alfred, Lord Tennyson's In Memoriam and became a popular phrase a few years later, when Charles Darwin introduced the concept of 'natural selection', which the economist Herbert Spencer reinterpreted as 'survival of the fittest'."