I think the one you are looking for is from the movie Bonnie mentioned. Here are the lyrics, from Song of the South dot net:

Words and music by Johnny Lange,
Hy Heath, and Eliot Daniel.
Performed by the Hall Johnson Choir
© 1946 Walt Disney Music Company


That's what Uncle Remus said.
That's what Uncle Remus said.
Listen now to what I say:
That's how the critters got that way.

The leopard's pappy got the gout,
From eatin' too much speckled trout.
His mammy dreamed of polka dots—
That's how the leopard got his spots.
That's what Uncle Remus said.
That's what Uncle Remus said.
Speckled trout and polka dots—
That's how the leopard got his spots.
More, more, tell us more!

The camel crossed the dessert sands,
With all them mighty caravans.
His bed was full of sandy lumps—
That's how the camel got those humps.
That's what Uncle Remus said.
That's what Uncle Remus said.
Bed was full of sandy lumps—
That's how the camel got those humps.
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The pig he saw his monkey friend,
A-swinging by his other end.
He tried the same thing on a rail—
That's how the pig got a curly tail.
That's what Uncle Remus said.
That's what Uncle Remus said.
Tried the same thing on a rail—
That's how the pig got a curly tail.
More, more, tell us more!
More, more, more.