Absolute unit that nearly got wiped out and then ended up on the back of a nickel.
Fun fact: Yellowstone's entire herd — the only wild, genetically pure bison in America — descends from just 23 animals.
Biggest lizard on the planet and they've decided a few tiny Indonesian islands are all they need.
Fun fact: Long assumed to kill with bacteria-laden saliva, they were found in 2009 to have true venom glands.