Alice Snuffleupagus is Snuffy's two-year-old sister, of the Snuffleupagus species. She is a lighter brown than Snuffy and wears a blue bow on her head. As a baby-upagus, she is just starting to learn about the world. She also likes to do whatever her older brother does, including roller skate. Her birthday is December 21st.
Alice first appeared on Sesame Street in Season 19 and was seen through Season 31. Although she was dropped from the show following that season, she continued to be seen with the cast on their Macy's Thanksgiving Day Parade float through 2008.
The Alice puppet is much smaller than Snuffy and is operated by a single puppeteer. Her eyes and mouth are controlled from inside the puppet. The performer wears a bodysuit with straps and buckles, that attaches to the inside of Alice's body. The suit is too small for the performer to wear the chest-mounted TV monitors that other full-body characters wear to watch their performance during the take. Between takes, an assistant can fan the performer's face, through the mouth. Her eyes are controlled by remote control, a first for the series. 
Behind the Scenes
A younger sibling for Snuffy was initially pitched in 1978, where Snuffy would've had a bipedal, younger brother.
A 1987 article in New York Magazine about the upcoming season of Sesame Street focused on Sladky's first screen test as Alice. The article offers a behind-the-scenes look at the process of creating Alice, as well as the producers' hopes for the character's popularity:
Stone looks over Alice as if she were a starlet. "You're a thoroughbred Snuff," he says approvingly. "But that's practically the only kind there is." A short discussion about Alice's blue ribbon is held with the control room. Its hue is too "hot" for the camera and must be exchanged for a paler shade.
"You know you're Aloysius Snuffleupagus's baby sister," Stone says, waiting to see how well Alice ad-libs.
Alice bats her lashes and gives Stone a nuzzle with her head. "Wishus," she says in a dove-soft voice.
"What's your favorite food, Alice?"
"How far is it to your cave?"
Alice rolls her eyes. "Far."
"Yeah, but how far?"
"How long does it take to walk there?"
"How many streets do you have to cross?"
"None by myself."
Ten minutes into her test, Stone looks down at her. "You're cute as hell," he says. "This could be another Big Bird." When Alice is introduced in January, Sesame Street's audience will decide if they agree. Stone walks away, and two assistants help Sladky out of Alice's body. She is sweat-soaked, and her face is drained. She and her husband, Jim, are former U.S. ice-skating champions. Being Baby Alice takes just as much out of her as the rink did. ”
- Sesame Street
- Sesame Street: 20 and Still Counting
- Big Bird's Birthday or Let Me Eat Cake
- A New Baby in My House
- Macy's Thanksgiving Day Parade
- "We Are Family" music video
- A My Name Is Alice (1989)
- Alice's First Words (1989)
- Bert and the Magic Lamp (1989)
- Come As You Are (1989)
- Splish-Splashy Day (1989)
- See You Later, Mashed Potater! (1990)
- Sleep Tight! (1991)
- We're Counting on You, Grover! (1991)
- Grover's 10 Terrific Ways to Help Our Wonderful World (1992)
- Elmo's Big Lift-and-Look Book (1994)
- Ready, Set, Go! A Counting Book (1995)
- Friendly, Frosty Monsters (2007)
- What Makes You Giggle? (2007)
- Love, Elmo (2009)