I'm quite sure that the version Frank McGrath posted is the one wanted, but I have here a semi-new version rewritten by Dominik Behan (to the same tune):

THE ZOOLOGICAL GARDENS
(Dominik Behan)

Chorus: Thunder and lightnin' it's no lark
When Dublin City is in the dark,
Would yeh care to go to the Phoenix Park
And view the Zoological Gardens?

1. I went up there on my honeymoon,
We saw the lions and the old baboon,
And we strayed for a while 'neath the silv'ry moon
Around the Zoological Gardens.

2. She says to me, me dear friend Jack,
Sure I'd like a ride on the elephant's back,
If yeh don't go outa that I'll give you a smack
Around the Zoological Gardens.

3. But Jack, says she, to give you yer due,
There's nothing jumps around as well as you,
No not even the big Australian kangaroo
Around the Zoological Gardens.

4. Oh Lord says I now don't be daft,
She says it's true and yer not to laugh,
But yer lovely and long like the spotted giraffe,
Up in the Zoological Gardens.

5. We left by the gate at Castleknock,
She says me dear sure we'll court on the lock,
Then I knew she was one of the rare old stock
Outside the Zoological Gardens.

Here's the notes of Dominik Behan (adding to Frank's explanation):

"The Phoenix Park is one of the best loved and most loved parks in Europe. In order to get to the Zoo, lovers have to pass the Hollow, and because anybody wanting a good court would be stupid if he passed the Hollow, very few people ever get as far as the Zoo until they are married with children..."

Wolfgang