Sid is a sloth who is one of the leaders of the Sub-zero Adventure Squad. He is portrayed as clumsy, fast-talking, and unpopular and is voiced with a lateral lisp.
He accidentally starts a fire in the first Ice Age film and learns how to do it properly towards the end and also shows this skill in Ice Age: The Meltdown, where he can carry a stick.
In Ice Age: Dawn of the Dinosaurs, he adopts a trio of dinosaurs, and is forcibly taken to the underground dinosaur land by their mother, requiring the others to come and save him.
It is revealed in Ice Age: Continental Drift that Sid also has a family and is also the grandson of Granny Sloth.
He will make his guest appearances (along with Manny, Diego, and the Sub-zero gang) in other projects outside of the Manny, Sid, and Diego's Adventures Series, such as Danny Phantom's Adventures of Short Circuit 2, Danny Phantom and Shrek's Adventures of Rio, and the several episodes of Captain Charles T. Baker's Adventures of Kim Possible.
Sid is voiced by John Leguizamo.