How is my terrier able to separate other animals into ‘dog’ and ‘not-dog’?
the Guardian -

The long-running series in which readers answer other readers’ questions on subjects ranging from trivial flights of fancy to profound scientific concept

What it is that enables a dog to separate other animals into “dog” and “not-dog”, even from a distance? My terrier can see another animal 100 yards away or more, and knows instantly if he is looking at another dog. No matter what the breed – from Yorkies to Great Danes by way of spaniels, boxers, labradors, rottweilers, greyhounds and generic...

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