SHOSHONE WHITE ANIMALS

Creatures, humanoid or anthropoid, were reported in the vicinity of Shoshone (Idaho) in April, 2005.  They were pure white.  They didn't, however, have ears or noses.  They had vestigial mouths.  They also seemed to be marsupial.  They were seen gorging themselves on fish and placing quantities of fish in their pouches.
These creatures are so bizarre that it seems unlikely the sighting is a hoax, but what are they, exactly?

When people say the USA could not contain strange animals, it is worth noting that conurbations and cities in the 48 states excluding Alaska and  Hawaii cover only 2% of the terrain.