999 - Cougars

If you're lying in bed tonight and you see yellow eyes glinting in your window, are you being stalked by a puma, a mountain lion, a panther, a catamount, or a cougar? Trick question--in North America, they're all names for the same species, Puma concolor! Isn't learning fun? Anyway, sleep tight!

This is an archival copy of the works from xkcd.com.