Who built the ark?

This is a song from my childhood (probably Primary School) that I've just remembered

Who built the ark?
Noah Noah
Who built the ark?
Brother Noah built the ark.

Now in come the animals, two by two
A hippopotamus and a kangeroo
Bum-bum-bum

Who built the ark?
Noah Noah
Who built the ark?
Brother Noah built the ark.

Now Noah said "Now shut that door"
The rain started pouring "and we can't take more"
Bum-bum-bum

Who built the ark?
Noah Noah
Who built the ark?
Brother Noah built the ark.

We weren't really supposed to sing the Bum-bum-bum bit, but we were kids, so we did.