Now I just ran this on "DOGPILE", a multi= search engine which I use a lot, and found out that this song was a cut on one of the special little 16 1/3 RPM records made for an automotive hi-fi sound system installed as an option in some 1956-7 Chrysler Imperials.

FMI:
href="http://www.imperialclub.com/Repair/Accessories/HiWay/Index.htm">Imperial
Highway Hi-Fi

From a listing of available records, here is the one on which "Rhumpy" is featured:

                                            JR 30

SIDE 1: TIGER (Bring 'Em Back Alive) (Story adapted by peter Steele and Hecky Krasno from Frank Buck's "Bring 'Em
Back Alive); FRANK BUCK Merrill E. Joels, narrator, with supporting cast. Vocals by the Southernaires. Orchestra
conducted by Spencer Odom RHUMPY THE RHINO. Craig McDonnell as Rhumpy, Karl eber, narrator, with supporting
cast and orchestra.

SIDE 2: SLUGGER AT THE BAT (Story by Peter Lyon and Peter Steele) (Music by Morris Surdin) with Jackie Robinson
and Pee Wee Reese with supporting cast. Carl Frank, narrator HOOK AND LADDER NO. 99: Authentic fire engine sounds
and story ALL ABOARD A COVERED WAGON with Mr. I. Magination, musical story. Paul Tripp as Mr. I. Magination.
Orchestra conducted by Ray Carter. Children: Judith Gail Krasno, Karen Eisenberg $2.25

Of course those are 1957 prices, and where you would get one of these records now, or how you would play it without one of the special automotive units, is beyond me. I would imagine that if any still exist, they would be quite valuable as collector's items.

You might try E-Bay if really interested.

Thanks for posting this; now I learned something, and I like to do that!