Is your clan capped at 18 members (6 of each age group)?

In Ancestors: The Humankind Odyssey, I’ve managed to find independent adult hominids to invite into my clan. After my clan’s catastrophe-prone first generation though, I’ve since gotten better at not losing clan members, and I have also been unable to find any independent hominids.

This coincidence leads me to believe that outsiders are only generated if you lose adult clan members and drop below six. I’ve also since turned on “full” HUD, and the clan status HUD element’s layout/size also suggests—but doesn’t conclusively say—that there may be a hard cap at 18 clan members.

This being Ancestors though, I don’t trust that I’m not just missing something. Is there simply a hard cap, or is there something else going on?

(I’m usually adverse to spoilers and that’s double for this game, but clan size is starting to feel like “invisible game wall logic” rather than a naturalistic part of the game’s puzzles, so this feels worth an exception.)