Who's Who in the Zoo is one of the cartoons that Warner would occasionally produce, particularly in the World War II era, that featured a series of loosely related gags, usually based on outrageous stereotypes and plays on words, as a narrator (in this case Robert C. Bruce) describes the action. The plot is substantially similar to that of 1939's A Day at the Zoo, except that Porky Pig (voiced by Mel Blanc as usual) appears as the zookeeper of the "Azusa Zoo," and that the now-discontinued Elmer Fudd is absent. Some excerpts:
In a comic "triple", a timber wolf is shown, then a gray wolf, then a "Hollywood wolf" (a frequent reference in the 1940s WB cartoons).
Other creatures include a "missing lynx", a "tortoise and the hair", "March hares" who march to a drumbeat, a down-on-his-luck "bum steer", an Indian elephant attired as an American Indian, and a bald eagle wearing a toupee.
There is also a running joke about a lion who is awaiting the arrival of the ice cream truck.
An Alaskan Bear who's known for hugging its prey to death picks up and starts hugging a defenseless sheep. When the narrator begs the bear to stop hugging the sheep, the sheep responds, in a feminine voice sounding like Sterling Holloway: "Oh, for goodness' sake, mind your own business!"
A group of seals that the narrator says only eat fresh mountain trout. Porky attempts to feed them a mackerel instead, claiming it to be indistinguishable, but a seal plants a sign saying "No substitutes accepted".
Some gags reference the then-ongoing World War II, including a black panther drinking cream from its dish, then noticing the dish is aluminum and throwing it into a scrap pile, a reference to the Salvage for Victory campaign; as well as a distressed rabbit father of dozens of babies given a note from the government to "increase your production 100%," as the song "What's The Matter with Father" plays in the background.
^Beck, Jerry; Friedwald, Will (1989). Looney Tunes and Merrie Melodies: A Complete Illustrated Guide to the Warner Bros. Cartoons. Henry Holt and Co. p. 125. ISBN0-8050-0894-2.