Binacle eggs are laid and hatch simultaneously on rocks. After some time, they move away from their sibling by swapping with a nearby rock. If two Binacle pairs meet, they’re much friendlier when one is related to the other.

Pokéologists found cavities in Barbaracle’s rock that let its 7 specimens communicate without alerting anybody else. Trainers should be careful to give affection to each Binacle within Barbaracle, not just the head. If a limb become jealous, it snaps off and leaves.