Having more thoughts on Eridian worldbuilding, this time about families.
While I love and greatly enjoy all the adorable fics, art and headcanons about Rocky, Adrian and Grace forming a little family unit together... I strongly doubt that Eridians have any real concept of the nuclear family.
The thing is that nuclear families (family units consisting of a married couple and any kids they have) are a relatively modern and largely Western invention; for most of human history and in most parts of the world households have been larger and involved extended family members, tending more towards clans than individual units.
Notably, this is also more common in more collectivist societies- and Eridians are supposed to be even more collectivist in nature than humans are.
Eridians make major decisions by joining together in large groups that form a single consciousness.
They need to watch each other sleep on an irregular timeline, which would be wildly impractical with two people who aren't stuck on a tiny spaceship together, and instead have jobs and obligations outside the home.
They traditionally stored food from hunting in large communal piles.
In the movie Rocky has a family crest that he uses to introduce himself, indicating a major focus on family/clan as a part of identity.
James Ortiz's headcanon about arranged marriage also fits, since those usually happen in societies that view marriage as a union between families, rather than between individuals.
All of this points to Eridians living together in large groups joined by kinship, and potentially friendship as well. They have many adults in the home that all support the family, watch each other sleep, and come together to make important decisions. And this family identity is an important part of how they see themselves and their purpose in the world.
And then there's the issue of Eridian reproduction.
When you put together that Eridians lay five eggs at a time, that they live for centuries, and that egg laying is easier than giving birth, you're looking at one Eridian mating pair having up to five kids at minimum, and dozens at maximum. Maybe in the past it evened out due to child mortality, but assuming they've largely solved that with modernity it's a recipe for massive, unsustainable population growth.
I've seen several fan explanations for this, but for me the simplest is that Eridians just don't put as much emphasis on individual couples having children as humans do. Each family generation is probably quite large, but only a couple kids in that generation will choose to have children of their own, and then those children will be raised by the family, It-Takes-a-Village style.
It's similar to how it was an evolutionary benefit for human families to have single, gay and elderly members: including childless adults increases chances of survival for the children the family does have. And quintuplets have gotta be a lot for one couple to handle, even with Eridian multi-tasking abilities.
If I can get even more out there, considering the collectivist nature of Eridians and the relatively detached method of laying eggs vs. childbirth/nursing, it's entirely possible that Eridians don't actually put that much stock in who a child's biological parents are. There are human societies that historically reckoned kinship similarly, referring to some or all aunts/uncles as parents, and cousins as siblings.
All of which is to say that again, large and tight-knit extended families are very likely the default for most Eridians.
And oh boy, the implications this has for the story!
Imagine Ryland "No close family, no friends, not even a dog" Grace, arriving at Erid to discover that he has not only been adopted by Rocky's mate but by his entire, massive family as well.
Imagine Rocky's relatives, many of whom are likely also engineers, working to maintain Grace's dome. Because that's what you do for family, and any family of Rocky's is one of theirs.
Imagine Rocky and Adrian having a clutch and Grace getting ready to be an uncle only to discover he is 100% considered a parent too.
Imagine this lonely, isolated person having a huge support system for the rest of his life.
It's wonderful, and I'd love to see it explored more.
