Why are Harley Davidsons called hogs?

Nearly a century ago, Harley's racing team, the Wrecking Crew, had a small pig as a mascot and one of the riders would do victory laps with the pig sitting on the bike's gas tank.

This earned the riders the nickname "hogs" and eventually people referred to the bikes as hogs, too.

Legend has it that this was the origin of the term "hog" when referring to a Harley.