Grumpy mules 'highly intelligent'

Mules are a hybrid of horses and donkeys

The legendary "bad temper" of mules is because they are intelligent animals who are mentally under-stimulated, claim researchers studying them.

Academics who carried out research at a donkey sanctuary in Devon found that mules were smarter than horses or donkeys.

The animals are hybrids of male donkeys and female horses.

The researchers tested the cognitive skills of the three species using buckets of food marked with symbols.

Six donkeys, six horses and six mules took part in the research at the sanctuary in Sidmouth.

Each animal was shown two food buckets marked with different symbols.

To gain access to the food the animals had to pick the correct bucket.

The mules were able to discriminate between more pairs of symbols than the other animals and were more consistent.

Hopefully our findings will ensure people change their attitudes towards mules Dr Britta Osthaus

Dr Britta Osthaus, psychology lecturer at Canterbury Christ Church University, said: "The mules' performance was significantly better than that of either of the parent species and got faster over a period of time.

"Hopefully our findings will ensure that people change their attitudes towards mules, which frequently have a bad reputation because they often are mentally under-stimulated and therefore might turn against humans or become destructive."

Leanne Proops, from the University of Sussex said: "The increased intelligence in the mule is a result of hybrid vigour, where the best genes of the parent species mix and match to produce hybrids with superior traits.

"This is the first study to show that hybrid vigour is able to improve cognitive function too."

The animal bred from a female donkey and a male horse is known as a "hinny".