When I walk my dog in the park I see many other dogs there too – collies, Alsatians, poodles, retrievers, Rottweilers, Labradors, terriers, mixtures of all these and more. My own dog is very much on the mixture side of things. I do not think of these different types of dog as ‘races’ of dog. For dogs, ‘breed’ is a concept that is helpful in identifying type, so people might ask what breeds combine in my dog to give her such a cheerful appearance. But they are all dogs, and from their point of view that is the key thing that makes them so interesting to one another.

Differences of height, weight, colour of fur, length of tail, floppiness of ears and other external characteristics are irrelevant to dogs, for whom the dogness of other dogs, their friendly or otherwise smell, and what sex they are, are the sole parameters of relationship. If only the same sort of