The "fluffy" tail is also a characteristic typical of Keepers (especially males), while leonine tail is found more often in Seekers males. Seekers of the Sun also have a very frequent case of oddly coloured eyes, which the clain believes to be an auspicious trait.
Keepers are said to be solitary and brooding, prefering an isolated life and living in small communities, while Seekers are hyperactive, cheerful and impulsive, and tend to get bored quickly. I wish SE respected this part of Miqo'te lore by giving Keepers more brooding/introvert emotes, but instead we got the same Seekers have.... that's a real bum, no one of my emotes reflect my Keeper nature.
EDIT: Probably obvious but since it's not there yet...
Keepers: Nocturnal, matriarchal society.
Seekers: Diurnal, patriarchal society.
