The dreams of animals

What do the dreams of nonhumans say about their lives? Animals may not ponder deep existential questions, but new developments in sleep research are beginning to push back against ideas that animals can't dream. Although what we experience when we sleep is too complex to be reduced to a collection of visceral automatisms, David M Peña-Guzmán, author of 'When animals dream: the hidden world of animal consciousness', discusses the latest research into nonhuman animal psyches.