Nighttime Howl
Credit: U.S. Geological Survey

This thermal image of a howling wolf was taken at the Grizzly and Wolf Discovery Center in West Yellowstone National Park. Wolves communicate using yips, barks, whines, growls and howls, but contrary to popular belief, wolves don't actually howl at the moon. Wolves are often heard howling during a full moon because they are more active during lighter nights, when they feel safer roving about in the bright moonlight.