I searched for [Pat Shaw] and the data-base came up with three items, but not these two:

A Lady Hippopotamus

A lady hippopotamus thought life was quite monotonous
Her mother never told her what was what
She was young and quite attractive but her glands were very active
And her love-life simply went to hippo-pot
She saw with awful clarity, her hippo-popularity
Did not extend to gentlemen she knew
And the hippo-poportunity for loving with impunity
Was not the hippo-proper thing to do

She was sad and she was lonely and she got the hippo-pip
'Til at last she took the fatal step to drink
Well it may sound quite irrelevant, but one day she met an elephant
And he of course to her looked hippo-pink
Now what happened, to be sure, was just a little bit obscure
But hippo-apparently she didn't think to stop
And now the wages of her sin are several hippo-picaninnies
Who have never really met their hippo-pop

and--not for the faint of heart:

I Had a Hippopotamus

I had a hippopotamus, I kept him in the shed
I fed him up on vitamins and vegetable bread
He was my dear companion on many cheery walks
I had his portrait done by a celebrity in chalks
bah-dum, bah-dum, bah-dum, bah-dum, bah-dum

The creature's popularity was wonderfully wide
His charming eccentricities were known on every side
He frolicked with a vigor in a dozen friendly tussels
You could not but remark upon his hippopota-muscles
bah-dum...

I had a hippopotamus, I loved him as a friend
But beautiful relationships are sure to have an end
Life robs us of our joys and deprives us of our blisses
My hippopotamus was a hippopota-misses (mrs.)

The housekeeper regarded her with jaundice in her eye
She didn't want a colony of hippopotami
She borowed a sub-machine gun from her soldier nephew, Percy
And showed my hippopotamus no hippopota-mercy

The house now lacks the glamour that the charming creature gave
The garage where I kept her is as silent as the grave
No longer can we wander thru the forest in the spring
No longer can I lead her thru the village on a string

I learned both by hearing them sung by friends and can't swear that they haven't changed in the (oral tradition) process.