The dog that never became a dog. He hadn't had to hurry his evolution into a coursing predator that could compete with true dogs.

The marsupial Tasmanian Wolf never managed to become a true dog. He was Australia's sole carnivorous coursing predator until humans reached that island continent, probably in the later stages of the Pleistocene Epoch. Those humans, ancestors of Australia's aborigines, brought their dogs with them. Their true canidae became the ancestors of today's semi-feral Dingos.

Unfortunately for the animal phylogenists call the Thylacine Cynocephalus, it couldn't compete with the true canidae. It was fierce enough, and strong enough. This illustration doesn't nearly do justice to its powerful, punishing jaw. It was lack of speed, adaptability and hunting resourcefulness that probably eliminated the Thylacine in Australia. Its fastest gait was more hop than run.

The Thylacine survived until very recent times in Tasmania, an island state of some 26,000 square miles just off Australia's southern coast, hence the popular name: Tasmanian Wolf. The San Diego Zoo, about a half century ago, had a specimen.

It was probably human trophy hunters who finally erased the last of this creature caught between conflicting epochs. In isolation it likely had a later start -- and then it didn't have to evolve as fast as did the true Canidae. When faced with the reality of those invaders it couldn't compete against them.