"Waaayo"? African-sounding song I heard as a boy and at a zoo.
From what I remember, that one word (probably spelled wrong) is the only lyric. I'm too awkward to record anything, but it went something like:
Bum. "Waaayo." Bum-bum bum, "Waaayo."
There was more than one voice, masculine.
It might be in Swahili? I'm quite sure my primary school had some sort of partnering with a school in Tanzania if that helps; we heard it in assembly while someone from there taught us (back in the mid 2000s).