"That's Nitwhite!" - Dr. Nitwhite's catchphrase
A pelican who is often mispronounced as "Dr. Nitwit," which he hates being called. In his segments, he presents his assistant Watson to a word which he thinks is the only one that has a certain letter pattern, but when Watson says a short speech with a word that has the same meaning, Dr Nitwhite types it down on his computer and becomes upset.
Dr. Nitwhite also made a few minor appearances outside his segment. In Farmer Ken's Puzzle, he told Theo and Cleo that "hen" is the only three letter word with "en" in it. However, Theo proved him wrong by saying the word "pen", which made him upset and went back to the lab. He later return claiming that "hen" and "pen" are the only three letter words with "en" in it. Unfortunately, he was proven wrong again when the announcer said the word "end" which made him upset again. In To the Ship! To the Ship!, he told Theo that "lip" is the only word with the letters "ip" at the end. However, Lionel showed up with the book "Mississippi Skip and his Pirate Ship" where Dr. Nitwhite learned that "ship" and "trip" also end with the letters "ip" at the end. And as he goes back to the lab, Theo yelled out "sip" which makes him even more upset.
- mom, pop, wow (The Lost Rock, Pandora's Box, Be Bop, Sylvester and the Magic Pebble / I Miss You, Stinky Face, My Dog Is as Smelly as Dirty Socks/Just What Mama Needs)
- yes, yet, let, bet (The Hopping Hen, Yo! Yes?/Very Loud, Very Big, Very Metal)
- boo, cool, fool, toodle-oo (Touching the Moon)
- Where is Chica (The Boy Who Cried Wolf)
- Sean and Chica Fly to the Moon (There's a Fly in My Soup, Earl's Too Cool/When I Was Five)
- at (The Sad Dad, You Can't Catch Me!)
- bun, fun, run (Bug Beard)
- eat, seat, deal, meal, dream, great, headache (Treats!)
- The Lost Rock
- The Hopping Hen
- Touching the Moon
- The Boy Who Cried Wolf
- Pandora's Box
- There's a Fly in My Soup
- Be Bop
- The Sad Dad
- Bug Beard
- You Can't Catch Me!
- Sylvester and the Magic Pebble/I Miss You, Stinky Face
- Earl's Too Cool/When I Was Five
- Yo! Yes?/Very Loud, Very Big, Very Metal
- He is similar to Dr. Nobel Price from Sesame Street, who was originally performed by Between The Lions writer Brian Meehl, as he finds words that he thinks are the only words in the English language that have a certain letter only to find out there are more than just that, like how Dr. Price invents things that he finds already exist.