The depiction of animals as intelligent, thinking beings with emotions has been the stuff of fairy tales, folklore and mythology in Western culture for centuries.
Until relatively recently, though, Western science has been less receptive to the idea that animals have a sophisticated form of consciousness.
We do think of some animals — like dogs, horses, dolphins or chimpanzees — as having superior cognitive capacities, or abilities to connect emotionally with their own kind or with humans.
But most of us wouldn't typically think of a sheep or a crustacean as having a rich inner life.
As science grapples with just how little it knows about the mysteries of human consciousness, it's also reassessing the complexity of animal minds.
Marc Bekoff, professor emeritus of ecology and evolutionary biology at the University of Colorado, and whose books include The Emotional Lives of Animals, Wild Justice: The Moral Lives of Animals, Canine Confidential and Unleashing Your Dog, argues there's very little debate anymore over whether animals have real consciousness.
More cognitive animals
"Some people like to draw some kind of taxonomic line. They'll say, 'Well, mammals have it all, but not birds or fishes or reptiles, amphibians or invertebrates,'" Bekoff told The Sunday Edition's host Michael Enright.
"But I don't think that anybody who looks at available data and also just uses common sense would debate that the number of animals in that cognitive, emotional consciousness arena seems to grow every day, actually."
It's a view that runs counter to the more traditional position that animals act primarily out of instinct.
Bekoff said animals are "hardwired" with certain behaviours to aid their survival.
"But what I think is really phenomenally interesting, from ants to wolves and chimpanzees, is the flexibility non-human animals show in different situations," he said.
"They're able to change their behaviour by pondering the situation in which they find themselves and show remarkable flexibility in behaviour to adapt to those situations."