....Could be something like extremophilic archaea here on Earth? Not sure how they treat each other, but they're usually quite friendly (beneficial, or harmless

....Could be something like extremophilic archaea here on Earth? Not sure how they treat each other, but they're usually quite friendly (beneficial, or harmless— never pathogenic or parasitic) to us mammals– Something about branched separation in biochemistry and highly diverse ecological niches making resource competition less of a thing, I'd guess. But that's not really "mutually assured destruction on a species level", so much as more to gain by working together– Which honestly is better.