"Muskrat Suzy, Muskrat Sam, do the jitterbug in muskrat land..."

Why? That's all I can think to say after hearing this song, which I did yesterday morning on Sirius' 70s channel.

Why would someone write such a song for an adult audience?
Why would it be so popular?
Why use a synthesizer to reproduce the sounds of muskrats (I assume that's what that noise is supposed to represent. BTW, this is one of the most dastardly uses of the synthesizer. The best use, IMHO, is by Ferris Buller when he synthesizes various bodily sounds).
Why did Captain and Tennille have another hit after this seemingly career-ending song?
Why do I somehow know almost all the words to this?

"And he's tickling her fancy, rubbing her toes, muzzle to muzzle, now anything goes..."

Just kill me now. Please!!