Whooping Crane
In 1941, only about 21 whooping cranes survived; today the only natural wild flock has grown to more than 500 birds.
North America
Wild Turkey
Wild turkeys were reduced to a few tens of thousands in the early 1900s; thanks to protection and reintroduction, there are now around six to seven million.
Wolverine
Wolverines can travel huge distances: one young male walked more than 800 km from Wyoming to Colorado.
Wood Frog
The wood frog freezes solid in winter: its heart stops and up to about two-thirds of its body water turns to ice, yet it thaws and hops away in spring.