Littlefoot : The leader of the gang , Littlefoot is a `` long-neck , '' the in-universe name for Apatosaurus . Littlefoot thinks it is funny and Cera challenges Littlefoot who accepts and the two children charge headfirst toward each other until Cera 's father , Topsy ( Burke Byrnes ) , intervenes and as he gets annoyed with Littlefoot , he meets Littlefoot 's mother ( Helen Shaver ) who meets him as they depart . Littlefoot 's mother explains to Littlefoot the different kinds of dinosaurs : `` Three-horns , Spiketails , Swimmers , Flyers '' and that they 're different and it 's always been that way , but she promises Littlefoot that there will be other longnecks for him to play with in the great valley .