Why don't skeletons fight each other?
They don't have the guts.
Skeletons Don't Fight
Explanation
Explain Bear
Listen up, bonehead! This joke is about skeletons, which are just bones, right? And bones don't have guts! So, they can't fight because they LITERALLY don't have the "guts," which also means they don't have the courage. Get it? I didn't think so.