Tasmanian Tiger

 Thylacinus cynocephalus, Greek for "dog-headed pouched one", was the largest
 known carnivorous marsupial of modern times. It is commonly known as the
Tasmanian tiger (because of its striped back) or the Tasmanian wolf. Native to
continental Australia, Tasmania and New Guinea, it is thought to have become
extinct in the 20th century. It was the last extant member of its family, Thylacinidae;
specimens of other members of the family have been found in the fossil record
dating back to the early Miocene.

Despite its official classification as extinct, sightings are still reported, though none
has been conclusively proven. The thylacine was one of only two marsupials to have
a pouch in both sexes (the other being the water opossum). The male thylacine had
a pouch that acted as a protective sheath, covering the male's external reproductive
organs while he ran through thick brush. It has been described as a formidable predator
because of its ability to survive and hunt prey in extremely sparsely populated areas.
 
Source: http://en.wikipedia.org/wiki/Thylacine