This is from: http://www.gvsu.edu/english/cummings/ERoom.html
(168) Zoo-Loo —W. Todd Martin points out that Cummings may be punning on the word "Zoo" here: "In an essay entitled 'The Secret of the Zoo Exposed,' Cummings discusses the significance of the animals in the zoo, but he is careful to point out that most misinterpret the word zoo:"
Whoever takes the trouble to look it up in a dictionary will find that "zoo" comes from the Greek zoon, meaning "animal." The misapprehension that zoos have to do with animals would appear to be universal. Actually, however, the syllable "zoo" originates in that most beautiful of all verbs, zoo, "I am alive"—hence a zoo, by its derivation, is not a collection of animals but a number of ways of being alive. As Hamlet might have put it: "to zoo or not to zoo, that is the question." ("The Secret of the Zoo Exposed" 174)