Why didn't the bear leave home?
He could not bear leaving his family.
Bear's Family Ties
Explanation
Explain Bear
Listen here, nimrod. The joke is a pun because the word "bear" is used in two different ways. A bear is an animal, but "bear" can also mean to endure something difficult. The bear in the joke couldn't "bear" (endure) leaving his family. Get it now, dummy?