The Border Collie is a working and herding dog breed developed in the Scottish borders for herding livestock, especially sheep. It was specifically bred for intelligence and obedience. It is very fetch-oriented. Border collies require considerably more daily physical exercise and mental stimulation than many other breeds. The border collie is widely considered to be the most intelligent dog breed. The border collie ranks 1st in Stanley Coren's The Intelligence of Dogs, being part of the top 10 brightest dogs. Although the primary role of the border collie is to herd livestock, the breed is becoming increasingly popular as a companion animal. The natural life span of the border collie is between 12 and 15 years, with an average lifespan of 12 years. The median longevities of breeds of similar size are usually 12 to 13 years. Rico, who was studied for recognising up to 200 objects by name. Another border collie, Betsy, was found to have a vocabulary of over 300 words.