Uncommon to the other creatures of the Red Faction, Houlos prefer subterranean areas for their habitats. Since their sensible eyes allow them to see in the night, they often dominate in dark caves.
Their feathers are made of complex carbon-based material, which guards them against most of the outside factors. They are very resistant to low and high temperatures. It’s a mystery of how they communicate, reproduce, and what is their social hierarchy, simply because they are difficult to find and whoever finds them hardly walks from their lair alive.
During the rescue mission on Proxima B, humans came across a large cave more than 1100 feet below ground level.