Darkvision: Accustomed to burrows and dim tunnels, ROUS can see in dim light within 60 feet of themselves as if it were bright light, and in darkness as if it were dim light. They can’t discern color in darkness, only shades of gray.
Nimble escape: ROUS can take the Disengage or Hide action as a bonus action on each of their turns.
Rodent resilience: ROUS have advantage on saving throws against being frightened.