The Malurians were a generally planet-bound species because their massive females eschewed travelling off-world and the males were bonded with them. However, the Malurians established colonies on the other planets in the system. (ENT - Rise of the Federation novels: A Choice of Futures, Tower of Babel) In 2267, the population in the Malurian system numbered four billion. In that year, the rogue probe Nomad sterilized the system, killing the Malurians. (TOS episode: "The Changeling")