Aka was the mother of Ryū.
Shiroi Senshi Yamato
She was owned by a boy named Seijurō, but the boy's grandfather Gohē abandoned Aka into the forest and lied that he didn't know anything. However, Aka managed to return back home and attacked the grandfather's arm. Tosaō, a fighting dog of Seijurō's brother, then killed Aka.
See more pictures in Aka (SSY)/Gallery.