In his new book, David Peña-Guzmán argues that animals that can dream have a sense of self, and therefore a far more complex kind of “animalhood” than we thought possible

By Simon Ings

When Animals Dream

David Peña-Guzmán

Princeton University Press

HEIDI the octopus is dreaming. As she sleeps, her skin changes from smooth and white to flashing yellow and orange, then to deepest purple and, finally, to a series of greys and yellows, criss-crossed by ridges and spiky horns.

David Scheel, Heidi’s human carer, has seen this pattern before in waking octopuses: Heidi, he says, is dreaming of catching and eating a crab.

The story of Heidi’s dream, told in the 2019 documentary Octopus: Making contact, provides the starting point for a barnstorming new book, When Animals Dream: The hidden …