Mama Sharptooth is a female Tyrannosaurus Rex, is Chomper's mother and the mate of Chomper's Father. She is one of the few female Sharpteeth in the series and one of the even fewer protagonistic Sharpteeth. Not much is known about her, though she has been shown to be immensely protective of her son just as her mate.
Mama Sharptooth debuted alongside her son and mate in The Land Before Time II: The Great Valley Adventure. During this time, Littlefoot, Cera, Ducky, Petrie, and Spike mistook Chomper's egg for one of Ducky's unhatched siblings, which had been stolen by Egg Stealers Ozzy & Strut. Not knowing whose egg it really was, they took it back to Great Valley where they lived. Sometime between then and late the next day, Chomper's parents discovered that he was gone and stormed into the valley in search of him. They found Littlefoot and his friends just after they had managed to lose Ozzy & Strut at a lava-filled canyon, and, apparently not realizing that Chomper was actually with them, the two Sharpteeth gave chase to the children as they fled in fear. As the gang took shelter in a grove of trees, the two Sharpteeth separated offscreen. Mama Sharptooth soon encounted Grandpa Longneck at a nearby lake and knocked him over after a short fight, but before she could finish him off, Mama flyer flew in and she chased after her, allowing Grandpa Longneck to escape. During the ensuing chase, Mama Sharptooth and Littlefoot crossed paths. She chased him, but, he and Chomper, working together, managed to briefly bring her down by tripping her with a vine. She quickly resumed the pursuit as Littlefoot and Chomper met up with Cera at a small cave, and the three took shelter inside just as Mama Sharptooth arrived. As she attempted to get at them, Ducky and Petrie, located in a nearby tree, distracted her by throwing coconuts from the tree at her. Angered, she attacked them, but went after Cera instead when she came to the aid of her friends. As she chased Cera, Spike halted her rampage by pushing a large rock onto her head, knocking her down.
As Mama Sharptooth lay agonized, Papa Sharptooth ambushed her temporary conquerors as they were leaving the scene. As Spike, frozen with fear, was about to be candy for Papa Sharptooth, Ducky jumped onto Papa Sharptooth's head to keep him from killing her brother. However, Ducky soon found herself in a precarious position of her own when Mama Sharptooth, having recovered offscreen, came up behind her as Papa Sharptooth was attempting to dislodge her from his nose. Mama Sharptooth moved in for the kill, but Petrie rescued Ducky and thus Mama Sharptooth accidentally bit her husband instead. The two Sharpteeth then had a brief domestic dispute before noticing Ducky and Petrie lying on the ground nearby and began closing in. At that very instant, they were intercepted by the adult herbivorous dinosaurs, with Mama Sharptooth being knocked down by Littlefoot's grandparents. Unable to defeat the grownups, the Sharptooth couple retreated into the forest empty-handed.
Later, when Littlefoot comes looking for Chomper, Mama and Papa attacked them once again, and after a brief chase, Littlefoot fell into a log and got his leg stuck. As Chomper went back for him, Mama and Papa began closing in on them. Fortunately, Chomper let out a small roar, finally causing Mama and Papa to realize that the infant Sharptooth was actually their missing son. As they prepared to leave the Great Valley, Littlefoot was caught by Ozzy and Strut, who attempted to get rid of him for good by throwing him off a cliff. Chomper heard him crying out and came to his aid, but got captured himself. Enraged, Mama and Papa attacked the villains who are trying to kill their son and Littlefoot and chased them out of the valley into parts unknown. Then, parting ways with Littlefoot and his friends, Chomper followed his parents out of the valley.
Mama Sharptooth, Papa Sharptooth, and Chomper later reappeared in The Land Before Time V: The Mysterious Island, in which Chomper attempted to hide Littlefoot & co. from his parents after they were marooned on the island. Unknown to them, a fearsome Giganotosaurus was also living on the island and attempted to kill Littlefoot and his friends. Chomper came to their aid, and his parents followed soon after. In the ensuing fight, the Giganotosaurus wounded both Mama Sharptooth and her mate with the former receiving a grizzly wound on her thigh with by her opponent's clawed foot and knocked unconscious the next second. Papa Sharptooth countered with a powerful tail swipe, knocking the Giganotosaurus off the cliff into the Big Water. However, as the Giganotosaurus stumbled and fell, his body swept Chomper off the cliff with him. Unwilling to forsake his friend, Littlefoot rescued Chomper while the Giganotosaurus was washed away in the current and presumably drowned. This couragous act led to Chomper's parents promising not to eat the heroes, with Mama Sharptooth herself even going so far as to nuzzle Littlefoot out of gratitude while purring.
She and her husband have not been seen since, though it is known that they apparently gave Ruby the responsibility of looking after Chomper when the two decided to live in the Great Valley after being separated from their families by Red Claw and his fast biters Screech and Thud.
- She, along with her husband, the original Sharptooth, as well as the Meanest Ever Sharptooth, are the only sharpteeth in the series to draw blood.
- When she notices Chomper and Littlefoot playing, she jokingly tells his son not to "play with his food" too much, implying she doesn't seem bothered with her son's taste in friends.