Dogs serve a purpose and have jobs to do. Farmers have used dogs to herd sheep and cattle for years. The working relationship between a Border Collie and his owner is an amazing thing to watch. The dog is focused to anticipate and implement any command the farmer may give, and the human focuses on the task to be accomplished. Some scientists speculate that without dogs, agriculture may not have occurred, as keeping cattle in herds would be almost impossible without a herding dog. Dogs are also trained to locate victims and cadavers buried under rubble from earthquake or other causes. The army and police train dogs to sniff out bombs, explosives, drugs as well as enter buildings to flush out fugitives. At home these dogs may be the family pet. Dogs can be trained to help people with disabilities by doing things or alerting the disabled.