Mama was the first cat to serve on the Blackfish, and while not every other cat to have stepped on board is her child, many are descended from her.
Mama is an old an ornery lady, who brokers no disrespect to her royal self, and shows no favor to anyone but her captain. Mama in particular seems to harbor a dislike of Nacre, after the latter in her cat form inadvertently tried to steal Mama's spot on Tides' bed.