Hidden away in a Sydney vault is a young, pickled pup. For almost 140 years, it's remained locked in its glassy tomb. But this is no ordinary pup. In fact, it's not a pup at all. It's a fetus of an animal more closely related to an Australian kangaroo. It was a marsupial which looked like a dog had stripes like a tiger, yet carried its young in a pouch. How the Tasmanian tiger, or thylacine, came to be extinct is a tragedy, and how it might live again is the pursuit of a scientific miracle. Is i