The Peanuts love to fight.
And I'm inclined to let them at this point, as it seems to be the kind of thing where if I ignore it now, it will solve itself before they get too rambunctious.
My sister and I fought like dogs for years, and finally we just stopped. So I'm hoping to accelerate that process.
Also. As a side effect, maybe Peanut #1 will be less tattly