Nicknames are a funny thing. Sometimes they only last for a short time, and sometimes nobody knows what your actual name is for years because you've been known as a nickname your entire life. Similarly, Theodore Cleaver will forever live as The Beaver. But often, you can live with something for so long that it almost becomes divorced from its origins, and you forget where that stupid nickname even came from in the first place. Today, we're taking you through two separate explanations for why Theodore is called Beaver: The explanation from the show, and the explanation from series creator Joe Connelly, delivered by The Beaver himself, Jerry Mathers.

In the series finale of Leave It to Beaver, the family took a stroll down memory lane by looking at a few photographs. During their reminiscing, Beaver asked how he got the nickname in the first place. June explained that when Wally was younger, he couldn't pronounce his younger brother's actual name, Theodore. Instead of saying the name, he pronounced it as "Tweeder," and his parents decided to call their son the similarly sounding "Beaver" instead. This is a very cute story, though some loyal fans were a little dissatisfied with the explanation for the name. 

Alternatively, Jerry Mathers explained the real reason that creator Joe Connelly chose the name Beaver during an interview with the Television Academy Foundation. Mathers explained that Connelly, who always wanted to write for television, kept an ever-updating notebook of people, names, and encounters that he could one day use as inspiration when writing material for a show. Connelly documented impactful experiences that happened to himself and his friends, and when he became a father, he began documenting his children's experiences as well.

Watch Leave It to Beaver on MeTV!

Weekdays at 8 & 8:30 AM, Sundays at 1 & 1:30 PM

*available in most MeTV markets

"All of the original Leave It to Beaver's come from real life," said the actor. "I'm not saying that each episode is one thing that happened to a child because they would take them and embellish them, maybe add different things. But the core of each episode is from real life, and they really did happen to a child."

Mathers went on to explain that Connelly also kept an alphabetized list of names of people that he had met throughout his lifetime, and one of them just happened to be the name of a shipmate Connelly once had during his time as a merchant marine in World War II. Mathers said that when it came time to develop his new show, Connelly flipped through his alphabetized list of names and got as far as the letter "B" before he decided that Beaver would be the perfect name for a character in the show.