In perhaps a sign that my gaming ideas have gone even further off the reservation than usual, I have begun thinking about ideas that would let me set a future RPG campaign on an alien planet. The most significant of these ideas is of a native and sapient alien species the characters would interact with. Aliens are something that shows up in science fiction all the time, but most of the legacy of popular depictions of aliens is rather poor, ranging from exaggerated cultural stereotypes (Star Trek) to under-considered biology (Star Trek) to a lack of consideration of external elements (also Star Trek). In writing something new I want to avoid this, while also bringing something to my game that would not exist if the inhabitants were just humans.
Perhaps one of the best depictions of alien life in my own recent memory comes from the PC game Sid Meier’s Alpha Centauri. The two dominant forms of life on the planet are a red fungus and psionic worms. While the aliens are not thought to be sapient at first, you discover through the game that these flora and fauna form a planet-wide neural net, taking the Gaia hypothesis to its logical extreme. Why Alpha Centauri succeeds so well with this is that these aliens are both believable and also utterly, truly alien. This also made the introduction of a more run of the mill bipedal species in the game’s expansion somewhat underwhelming.
The Alpha Centauri example shows that you can make truly new and weird aliens, but you have to remember that the sort of interactions that your characters will have with these aliens will not represent communication or diplomacy in the conventional sense. If you want to create alien life that organizes itself like humans do (and are not, say, a fungus), you run into more limitations. The key is to slot in somewhere between “psionic fungus” and “humans with latex head ridges.”.
Let’s assume that you want to include intelligent aliens. Intelligence evolves in a set of narrow circumstances, so while “humans with latex head ridges” is an unrealistic paradigm, giant insects or lizard people are not necessarily better. This is the one failing in the Alpha Centauri example…it’s not clear why the worms and fungus evolved psionic abilities. The worms make a bit of sense, as they produce terror in their prey…but it’s still odd. The focus on these more interesting flora and fauna also left the planet devoid of an ecosystem that let you understand exactly what the worms were either eating or defending themselves against.
Ecosystems imply the setting against which intelligence develops, so thinking about set and setting of your alien world helps establish what your species will look like. Human evolutionary biology, likewise, provides some key examples of what circumstances make intelligence beneficial, and therefore will help a species evolve to become sapient. Now, humans evolved from an ape-like species that were opportunistic feeders. Tool use came from many theorized places, including the ability to break the bones of kills picked clean and eat bone marrow. This kind of scattershot diet helps explain why intelligence was a favored trait, because advanced memory and the capacity for logic would help pre-humans find food that they couldn’t compete for with either predators (who were larger and stronger) or scavengers (who were faster and sometimes could fly). Feeding isn’t the only reason intelligence would be a favored trait, but it’s a strong one in a relatively short list. When you consider the number of behaviors that do not require sapience, the only things likely to make it an evolutionary benefit require actual thinking about a large number of discrete scenarios, specifically ones which instincts are unlikely to prepare you for. In general, situations of stress (food or water scarcity, intelligent and/or large predators, rapidly shifting or dangerous weather) are more likely to favor intelligence. Once again, though, it’s important that the threat is a dynamic one…if the main threat is and always will be a lion, evolving the ability to run really fast is more likely than evolving intelligence.
So after self-awareness comes language. Once again, while many animals have the ability to communicate, language is, whether written, spoken, or something else entirely, a construct that can expand to fit emergent concepts as they come up. As such, I honestly believe it goes hand in hand with sapience, along with other interpretive media like visual and sculptural art. Of course, how this actually works is likely to change a lot in differing environments. You want to make things really weird, look at ancient sculpture and note what parts are exaggerated. Think of what an alien would look like and think about what they’d exaggerate in their sculpture. This is the point where we start to leave evolution and get into anthropology, and this is where it gets interesting.
So form follows function when talking about the body. Humans developed cooking as their primary way to prepare food because it saved a lot of time…prior to the presence of fire as a common technology, humans chewed. A lot. This constant chewing made eating a much more involved and significant activity than it is now. That said, cooking doesn’t have to be the primary mode of food preparation. Imagine a species who prepared their food with acid…basically an entire culinary framework built on ceviche, if that helps make it more logical. They’d likely be from a biome where fire is less important (i.e. where it’s warmer), and they’d likely have significantly more gut bacteria, as acid-denaturing food doesn’t kill as much bacteria as cooking it. This would be truly odd from a human perspective, but based on what cooking actually got us (less time chewing), it could have happened and may happen on another planet.
Then, let’s mess with a few other things. Let’s say the two eyes are arranged vertically on the species’ head, and that sexual attraction is based on scent instead of sight. In both of these cases, the changes would result in something quite alien, but they don’t stray too far from normal biology for good reasons. In the case of eyes, there’s likely not that much of an advantage for more than two eyes, and interesting organs like insectoid segmented eyes would be very difficult in a human-sized form (and the aliens would likely be a similar size if they’re also evolving from opportunistic predecessors…too small and they’d be vulnerable and have small brains, too large and the square-cube law makes it hard to get enough blood to a proportionally necessary brain). Similarly, sexual reproduction can nearly be assumed, as sporing or other asexual means are unlikely to produce the genetic variation necessary for sapience to arise. Also, despite the number of times it shows up in science fiction novels, more than two biological sexes are highly unlikely simply because each additional sex reduces the probability of a successful mating significantly.
So there are constraints. An alien race is likely to be a similar size as us, reproduce sexually and have a varied diet. That said, they may not be symmetrical in the same way we are, their physical manipulators could be quite different, and the presence and attitude towards hair or even chitin could be varied. And it’s worth noting these assumptions all stem from a planet which humans could colonize… there may be intelligent aliens on a world with an atmosphere that’s 15% ammonia, but if humans can never go there it makes this exercise a tad less necessary.
Ultimately, alien species introduce interesting story opportunities when they get to clash with humans. On a planet that can support both, another species could be competitor or collaborator. And knowing how humans have treated each other in the past, it could get quite nasty. But all of this makes for some great story potential.