Yoko Is one of three baby dinosaurs Sid adopts. He is darker than his brother Egbert and sister Shelly, and has orange eyes rimmed red. He was the one who did not share the tree trunk he holds in his mouth, and the one Sid washing in the river. But despite his havoc, he still loves both his adoptive ”mother" Sid and his real mother with all his heart.

His name is a pun referring the yoke of an egg.