She acts as the leader of the pack.
She is the biggest of the four, and for some reason slowest, which might be due to age. She is the same color as her son.
Little Das' HuntEdit
She is first seen coming from behind a bush she was hiding at while her three children channeled the juvenile Maiasaura duo Buck and Blaze, and manages to bite the former's right-thigh, only for her son to head-butt her in excitement causing her to lose her grip on the hadrosaur, who escapes. She immediately reprimands Das for his impulses while they stay hungry for tonight.
The next day, she had been monitoring the Maiasaura since last night: even though Buck escaped, Das' mother did inflict some major damage to the hadrosaur and nature would certainly take its course, however she didn't want her son to participate again in fear he'll screw up again, so she tricks Das into keeping watch while she and her daughters sneak off to finish what they started. Ironically Das still screws them up anyway by spooking (and chasing) a herd of Einiosaurus, who fled to the Maiasaura and therefore the hunt fails again, Das' mom personally punishes him for it by biting his muzzle.
Some time later, she gives her son another chance to prove he can hunt and they go after the Maiasaura again. While Das again chases the two juveniles, his mother and sisters lie-in-wait. Blaze almost runs into them, but they ignore her in favor of Buck, who takes shelter with the Einiosaurus who form a ring around him, and allow him to getaway, but the tyrannosaurs soon notice and pursue him. Even though Buck no longer had energy to run, the Daspletosaurus don't bother rushing in to finish him, and get distracted momentarily by a Quetzalcoatlus that had been killed by a geyser. Her son sniff's it and sneezes because of the odor. They ignore it and continue after buck.
When the volcanic-cloud began darkening the landscape, the tyrannosaurs navigate with their noses and ears. They eventually find Buck, who finally has gotten too weak to stand, but they first gain back the energy they lost from the trek before eating. However about a few hours later Das' mom has taken notice of a approaching pyroclastic-flow which she see's as a threat. Despite finally having a chance to eat, she chose to keep herself and her family alive first and they all retreat. This though would be futile as the pyroclastic-flow is faster and it reaches them a minute later. The mother Daspletosaurus was the first of her pack to die (her young perished not long after).