Evolutionarily makes sense go me, tho I feel like it’s impossible to forget the stench of rotting flesh of your own species. People who work in true crime often say that it’s super distinctively human. The author might have a reason for that too tho.
I think they might not be exposed to it as much as they used to and probably forgot about it while in space because they probably would immediately get rid of the body's
You're looking at this the wrong way. It is very unlikely the aliens cannibalize themselves, since they also think their corpses reek.
Also, as the main characters demonstrated, they die VERY easily. It's very easy to kill them and they are quite physically weak.
However, they release a bad smell and taste bad to make them unappetizing to predators. Predators learn "this prey smells bad and tastes bad, so it's not worth the energy to kill it because you can't even eat it." Additionally, the bad odor warns other members of the species that one of them was attacked/killed, so they should stay away from that area (OR it summons more of them to come help fight). That's more likely how it would've developed evolutionarily.
The MC is probably just a freak random evolution who evolved into a predator who can eat them. Just like some animals are specialized in eating and digesting stuff like carrion or poisonous plants. It's just a random mutation that was selected for over time as their great amount of food options allowed them to reproduce more. MC is probably just the first generation.
You can't just evolve for something your species doesn't know exist. The species first has to be exposed to it and do what they can but their child will have slight adaptations then it goes on. This is why I believe that although it stinks they might have cannibalized at a certain point. Either way I think as more goes on we'll have to see lol
You absolutely can evolve to something that doesn't exist. All evolution comes about through random mutation. Children do not "adapt" in their lifetimes. They are born with the genetics and if they have beneficial genetics, they reproduce. Over time, individuals with good genetics survive longer and reproduce more than individuals with bad genetics. How do you think these differences arise? Through random mutation, which can be good, bad, and neutral.
Only the good ones get selected for and survive to reproduce, and the bad ones die off. The neutral ones just get passed around but not specifically selected for unless suddenly the environment changes.
For example, the black plague wiped out a huge percentage of the human population, but some people had a previously benign/neutral immune mutation that allowed them to survive. This mutation did very little for them until the plague started killing people without it. That's how evolution works, it always originates from a random mutation or change, which then is selected for when environmental pressures change.
She seems to be the only one that's capable of eating these aliens. What's even weirder is the stench they release, this might be a mechanism that triggers when they die to scare off predators and to give a warning to others. Ofc they are extremely advanced and probably don't die easily now so they more the often forget. Then here's the problem....how does the smell go away? Simple....they eat their corpses. Sometimes this sort of scent mechanism can backfire and actually tell predators where they are at so they have to have some way in stopping it. The issue is they also taste disgusting so they end up developing a taste for their own flesh. Ofc they over time probably forgot this. Now why does the main character have this taste? Well she was frequently beaten to the point of bleeding, there could have been an exposure point, some of their DNA could be highly contagious(?) and possibly could alter other DNA and considering her teeth aren't normal there might be other parts of her that's been changed one of which is her metabolism and sense of taste.