|Information in this article is non-canon|
Ducky's aunt, shown in a comic called The Land Before Time: 3D Adventure, and also mentioined in LBT XII to be a Sleep-Swimmer, is shown in LBT 15 and LBT 20, among others.
In LBT XV, she lives up to the Bigmouth name, talking a lot and nearly boring Littlefoot and his friends to death. She at first starts talking about Sharp Beaks, but later talks about fast water, her family, the day she built her first nest, and many other things. Eventually, the kids decide to have some talk to her, while the others slip away. Ducky was the last one to leave, leaving her aunt talking to herself, not knowing they were gone.
Later, Ducky's aunt finds the kids after they find Ptero and she scolds them, and they pretend to be glad to see her and all that so they don't get punished.
Later, she resurfaces again when they are about to play a game and begins rambling about old games dinosaurs used to play when she was younger. The others are bored, but Ptero, who knows nothing about Flattooth culture, is very interested.
It is presumed that she fought in the final showdown with Agatha, as she is around immediately afterward, and begins rambling again, boring everyone.
In LBT 20, after Ducky runs away, after hearing that Spike might leave for good as his Aunt Stella has been found, Ducky's aunt , after her mate had said that maybe the rebellious Ducky could do with a night of sleeping alone, rebukes him, reminding him of how he was to his cousin's fiance at their union ceremony when she was reluctant to tie the knot.