The moose and wolves of Lake Superior battle.

Flying squirrels leaping through the air.

Sometimes animals get a second chance.

The Asian carp, an invasive species, travels through North American waters, eating, breeding and decimating native fish populations.

Researchers continue to fight for the survival of the Lake Erie Watersnake, a species on the brink of extinction; a new source of food could mean the snakes have a future after all, so long as the lake's algae blooms cooperate.

Some people are fighting to save the endangered massasauga rattlesnake, which was vilified for years.