Tuck is a baby triceratops, the second son of Trudy and younger brother of Tank. He lives with his brother and mother at Triceratops Trail Station. He can not talk or walk very well. Most of the times he is crawling or being carried by Mrs. Pteranodon. He first appears in "Tank's Baby Brother" at first Tank wasn't well when he was having more attention, but in the end he turns up on him, he just wants to do want Tank does.