Why did the elephant get kicked out of the swimming pool?

This joke plays on a classic comedic device: wordplay, specifically a pun. The humor hinges entirely on the double meaning of the word "trunks." In the context of an elephant, "trunks" refers to its iconic long, prehensile nose, which it uses for breathing, smelling, touching, grasping, and even showering itself. However, when we think of a swimming pool, "trunks" takes on its other common meaning: men's swimming shorts.

The setup creates a humorous image of an elephant trying to enjoy a dip, only to be foiled by a misunderstanding of pool etiquette. The punchline subverts expectations by referring to the elephant's actual anatomical trunk, rather than the swimwear one might assume it's wearing. This unexpected twist, combining the animal's defining feature with a common item of clothing, is what makes the joke silly and memorable, relying on the listener's ability to quickly grasp both interpretations of the word.