Ray Romano
Manny (voice)

John Leguizamo
Sid (voice)

Denis Leary
Diego (voice)

Goran Višnjić
Soto (voice)

Jack Black
Zeke (voice)

Cedric the Entertainer
Carl (voice)

Stephen Root
Frank / Start (voice)

Diedrich Bader
Oscar (voice)

Alan Tudyk
Lenny / Freaky Mammal / Dab (voice)

Lorri Bagley
Jennifer (voice)

Jane Krakowski
Rachel (voice)

Peter Ackerman
Dodo / Freaky Mammal (voice)

P.J. Benjamin
Dodo (voice)

Josh Hamilton
Dodo / Aardvark (voice)

Denny Dillon
Glyptodon (voice)

Mitzi McCall
Glyptodon (voice)

Tara Strong
Baby Start (voice)

Chris Wedge
Dodo / Scrat (voice)

Kristen Johnston
Sylvia (voice) (uncredited)

Darin De Paul
Additional Voices (voice) (uncredited)

Dann Fink
Dodo (voice) (uncredited)

Patrick Pinney
Various Mammals (uncredited)

Phil Proctor
Various Mammals (uncredited)