Additionally, they are prized as sporting and hunting dogs. Some Labradors shed considerably; however, individual Labradors vary. Labrador hair is usually short and straight, and the tail is quite broad and strong. The webbed toes of the Labrador Retriever make them excellent swimmers. Some dogs are sold as silver pure-bred Labradors, but purity of those bloodlines is currently disputed by breed experts including breed clubs and breed councils. Although it has not been conclusively proven that the silver Labrador is a product of crossbreeding the Weimaraner to a Labrador, there is good evidence in scientific literature indicating that the Labrador has never been identified as carrying the dilute gene dd.