Maybe they can photosynthesize carbohydrates from the sunlight and carbon dioxide on Mars and use them for energy, but also be able to ingest and use the carbohydrates in food? Like a combination of plant and animal physiology, although it could be something like coral or lichen where they harbor symbiotic algae or bacteria in their skin to do the photosynthesizing for them. This wouldn't provide nearly enough energy to be able to move around at any human-like activity level daily at Mars' distance from the Sun, but perhaps they spend much of their time on Mars building up energy reserves and not moving much and then expend it in short bursts of activity (and we only see those periods in the comic, because, well, it's be boring showing the 99% of their time when they're just standing around in the Sun). But when they get to Earth with its much more abundant food, they can simply eat that and go off of its energy.
Statistics: Posted by Philadelphus — 13 Jun 2025 19:00
