How did Theodore Cleaver get the name Beaver in the old TV show 'Leave It To Beaver'?

In the old TV show "Leave It To Beaver," Theodore Cleaver got the nickname "Beaver" because his real name was Theodore, which sounds like "Theodore Beaver." His older brother, Wally, initially called him "Beaver" as a mispronunciation of his real name. The nickname stuck and became his commonly used name throughout the show.