Dogs are frequently portrayed as being almost as intelligent as humans, with Lassie the collie among the foremost examples in fiction. Picture: Max Pixel

London - It might surprise fans of Lassie, but dogs are no cleverer than pigs, horses, sheep – or even pigeons.

Man’s best friend has unexceptional brain power compared with most other animals, an analysis of 300 scientific papers into dog IQs has found.

And scientists who test them can be biased towards finding dogs are cleverer than other animals such as chimpanzees, the researchers said.

Dogs are frequently portrayed as being almost as intelligent as humans, with Lassie the collie among the foremost examples in fiction. For instance, it is often claimed dogs can navigate very long distances to find their way home. But the researchers say the evidence for this is "largely anecdotal" and spotted hyenas do it better.

The researchers, from Exeter University and Canterbury Christ Church University, found the abilities of dogs were at least matched by several other species. 

While dogs are considered good at sniffing out a scent, pigs might even be better at it, and the domesticated horse also has a keen sense of smell, according to the study reported in the journal Learning & Behaviour. The authors say a dog’s whiskers are less sensitive than those of cats and seals. In the case of vision, although they can distinguish different faces, so can chimps, pigeons and sheep.

And many animals apart from dogs can identify individuals from the sound of their voice, including the spotted hyena, the Asian short-clawed otter, the dwarf mongoose, the domestic kitten, dolphins and (once again) sheep.

Dr Britta Osthaus of Canterbury Christ Church University said: "We are doing dogs no favour by expecting too much of them. Dogs are dogs, and we need to take their needs and true abilities into account when considering how we treat them."