Ruby (a.k.a. "Responsible Ruby" is a main character in The Land Before Time XIV Journey to the Brave The Land Before Time TV series. She is an Oviraptor, which is called a "Fast Runner" in the series. She has not yet appeared in any of the Land Before Time movies, as she was only introduced in the TV series.
Ruby is often the voice of wisdom among the young dinosaurs, able to explain matters the others do not understand. She has a calm demeanor and shows kindness and empathy to others. A strange habit of hers is to sometimes immediately repeat herself in a "backwards" way. For instance, she might say as a greeting: "Hello my friends; my friends hello!" She may be considered the "opposite" of Chomper, being female, calm, and more relaxed than him (she preferred to relax in warm mud over playing a sport with him in one episode). She is also older and smarter due to more experience in life.
As seen in flashbacks in the series, Ruby lived with her family in the Mysterious Beyond until Red Claw and his Fast Biters, Screech and Thud, posed a threat to them. Chomper suggested that the two of them travel to the Great Valley, and meet up with his friends Littlefoot, Cera, Ducky, Petrie and Spike. Chomper's mother and father had apparently given Ruby the responsibility to look after and protect Chomper, as stated in "The Cave of Many Voices".
In a flashback in "The Star Day Celebration", just before Ruby and Chomper make their way to the Great Valley, Ruby is saying goodbye to her family, and her father reminds her to study how the residents of the Great Valley cooperate with each other. Her mother then adds "Someday it may save us from...", at which point she is interrupted by Chomper's warning that Red Claw and the Fast Biters are close at hand, and he and Ruby set off. This scene implies that Ruby is on a mission to learn how the inhabitants of the Great Valley work together as one herd, though they are of diverse species, so she can communicate this information to the residents of the Mysterious Beyond. They can then, in turn, use this knowledge to defeat or drive off Red Claw and his Fast Biters.
Ruby has a mother, a father, and two siblings. They have appeared in "The Star Day Celebration" and "Return to Hanging Rock". Her parents have wrinkles, implying age. The Mother is pink and the Father is blue. The Father also has an elderly-like voice. Her siblings are also pink and blue.
Ruby's age is not known in the tv series but she older then the gang it might be that she is an 11-year old oviraptor that was born last during the time when littlefoot and his friends were born, but she was born in the mysterious beyond in that time.