Of all the questions people email me about the show, the one that gets asked the most is "Was it Muttley or some other dog who would get a medal or a snack and hug himself with glee, jump into the air and float down like a feather? Please answer, the confusion is driving everyone here at the office crazy". The reason for the confusion is easy, because there were actually two cartoon dogs who did the very same thing.  The first was Snuffles, who appeared on the Quick Draw McGraw show almost a full decade before Muttley made his TV debut.  Snuffles would perform his bit of anti-gravity glee when he would get a doggy snack.  Muttley on the other hand, went into his floating euphoria when his master, Dick Dastardly, would give him a medal.

The Voice of Muttley

Our favorite snickering hound  was voiced by the prolific vocal talent
of Don Messick, who was also the voice of Scooby Doo.

He provided many of the voices for the Wacky Races, Dastardly & Muttley,
and the Perils of Penelope Pitstop, including Prof. Pat Pending, Little Gruesome,
Klunk and Zilly, and many of the members of the Ant-Hill Mob.

He is also the voice behind such memorable characters as Dr. Quest
from Johnny Quest,  the Flintstones Bamm-Bamm,
The Jetsons Astro, Yogi Bear's Boo-Boo and Ranger Smith,
and so many others from his forty year career.

and then came Mumbly...

Another question I often get is "Didn't Muttley have his own show
where he played a Detective?"  The answer is no, but there was Mumbly.

The Mumbly Cartoon show aired in 1976.  It featured a detective dog
  dressed up in a trenchcoat and solved crimes using his dog senses
and drove around in a beat up old car.  If you crossed Muttley and Columbo,
that was Mumbly.  The character was also featured in the laff-alympics.