Attempts have been made to line breed to a standard type, but a lack of proper records and the inability to substantiate bloodlines, plus the occasional introduction of new blood have prevented official recognition of the breed. One theory is that the name Koolie stemmed from the derogatory term 'Coolie' that was used to refer to immigrant workers in Australia. Another is that it resulted from the German accent being placed upon the word 'Collie'. Temperament Breeders describe Koolies as being extremely active, intelligent, anxious to please and fun-loving. They also make good watchdogs as they are not aggressive but they will bark to alert their owners.
Breeders say they are good with small children.
Inherited deafness can be a problem in merle coloured breeds. The average lifespan of the Koolie is quite long, around 15 years, possibly longer. Breeding An average litter size is six. Merle coloured dogs, when bred together, produce a litter, of which 25 per cent will be white, deaf and blind. These pups have to be killed.