Lyric discussion by jordan strange 

Cover art for At The Zoo lyrics by Simon and Garfunkel

I think this song is saying that humans and animals have more in common than we admit. I believe it's a call for animal rights.

"Orangutans are skeptical Of changes in their cages, And the zookeeper is very fond of rum."

It's just about what it means to be a living thing. We're all the same.