Animal Jokes
Question & answer
Why do crabs never give to charity?
Because they're shellfish.
Behind the Groan
A Shellfish Excuse
Shellfish names the group of animals that includes crabs, but it sounds nearly identical to “selfish.” A selfish crab would keep everything instead of donating to charity, so its biology doubles as a character flaw. Ask the setup like a genuine question about generosity. Say “shellfish” clearly and let the sound-alike complete the explanation without extra wording.