
WORKERS at the in Nairobi, Kenya, claim that elephants know they will be looked after at its rescue centre, even if the animals have never been there. Elephants that have had no contact with the centre, but know others who have, often turn up with injuries that need attention. That suggests not only abstract knowledge, but relatively sophisticated communication of that knowledge. Either that, or wishful thinking on our part.
The extent to which non-human animals 鈥渒now鈥 things is difficult to assess. The attribute known as 鈥渢heory of mind鈥 鈥 the ability to know what others are aware of 鈥 has been demonstrated, although not always conclusively, in elephants, chimps, parrots, dolphins and ravens, for example.

Inside knowledge: The biggest questions about facts, truth, lies and belief
Forget alternative facts. To get to the bottom of what we know and how we know we know it, delve into our special report on epistemology 鈥 the science of knowledge itself
Dolphins are even aware of lacking knowledge. Train a dolphin to answer a question such as 鈥渨as that a high or low-frequency tone you just heard?鈥 and they give sensible answers, even giving a 鈥渄on鈥檛 know鈥 when the right response isn鈥檛 clear. Some primates spontaneously seek further information when posed a question that they can鈥檛 answer, suggesting they know both that they don鈥檛 know and that they can change that.
Things look more mixed when we consider abstract knowledge: the ability we have to understand abstract properties such as weight or force, and squirrel away knowledge gained in one situation to be applied in some future, different context.
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Great apes instinctively know that, of two identical cups on a seesaw, the lower one is more likely to contain food. 鈥淭hey have a spontaneous preference, from the first time, for the lower cup,鈥 says Christoph Voelter, who researches animal cognition at the University of St Andrews, UK. 鈥淭hey seem to have certain physical knowledge about the world.鈥
New Caledonian crows, on the other hand, don鈥檛 have this know-how and make 鈥渕istakes鈥 when assessing which stones will exert the most force on a lever to release food. 鈥淐rows aren鈥檛 using knowledge of force when initially solving the problem,鈥 says Alex Taylor of the University of Auckland, New Zealand 鈥 rather, they seem to use trial and error.
Great octopus escape
There is evidence of animals showing regret at missed rewards, and knowledge of others鈥 deceitful behaviour. But we can only infer an animal鈥檚 state of mind from our observations, and inference rarely tells the whole story. Take the daring escape of Inky the octopus when his tank was left open at the National Aquarium of New Zealand last year. We might conclude from the way he did an eight-legged runner that he knew he didn鈥檛 want to be there. Or from how he seems to have made his way out of the building via a 50-metre drainpipe that he knew (or sensed, at least) it led to the sea. But in the end we can鈥檛 know whether the escape was planned or just opportunistic.
Santino the chimpanzee is definitely a planner. He knew he would want to throw objects at visitors to Furuvik Zoo in Sweden when they came, so broke the concrete in his enclosure into discs suitable for hurling, and made a pile of them. Chimps in the wild have been observed to plan breakfast, sorting out in advance what they鈥檒l eat, where they鈥檒l get it and .
But there鈥檚 still something crucial missing. A human toddler given a new object will investigate it thoroughly, checking through all its properties. 鈥淗umans perform these natural, systematic experiments to discover how the world works,鈥 says Voelter. 鈥淲e don鈥檛 have any evidence so far that other primates are the same.鈥
This innate curiosity and our unsurpassed linguistic ability allow us to accumulate a huge, almost undoubtedly unique repository of abstract knowledge about the systems and objects around us. You couldn鈥檛 teach a chimp quantum mechanics.
But we shouldn鈥檛 diss animal abilities. After all, crows know who you are and can hold a grudge against you for years, found of the University of Washington in Seattle. At least they don鈥檛 know where you live, says Marzluff. 鈥淚n my experience they must see the person, out of the house, to respond to the person,鈥 he says.
This article appeared in print under the headline 鈥淒o animals know things?鈥