Headscratchers / All Tomorrows

• So the Mantelopes, having large, sapient brains, degrade into beasts because they have... no opposable thumbs? Dolphins also have no manipulatory appendages whatsoever, yet evolution found enough incentive for them to be intelligent...
  • Right? Increased intelligence would be generally beneficial, and for a variety of things: avoiding predators, communication, social dynamics, and whatever manipulation they can accomplish. It wouldn't just evolve away, as there isn't much to gain from losing it; dumber mantelope wouldn't have a better shot at survival.
  • The Mantelopes do retain vestigal thumbs as dewclaws and have lips that look semi-prehensile. It's likely that as an intelligent species they will still be able to find a way to make this work.
  • Keep in mind that by their very nature, carnivores on average have to be more intelligent than herbivores, since brain power is necessary to hunt for active prey. It's no coincidence that most of the intelligent species on Earth evolved from carnivorous or omnivorous ancestors. Elephants are a notable exception, but they still feed in a manner conducive to the evolution of prehensile appendages, and thus intelligence— they're browsers, not grazers. The Mantelopes aren't anything like that. They're grazers, which means they don't have to think or reason to find food because food is all around them. There's no evolutionary incentive to invest in a large brain and a prehensile trunk if all you eat is grass. For a grazer, a big brain is a liability.
  • A liability how? If anything, a smarter grazer would be able to better escape predators, work together as a group, and better find food and adapt to changes. While intelligence isn't necessarily a goal per se, or a standard of "more evolved", it's nonetheless such a far too useful adaptation to get rid of once it's there, and it's unlikely that there will be selective pressure specifically against the smart ones.
    • Like any other adaptation, there's a trade-off - A big brain hogs energy and takes a long time to grow. The question is not "is there a benefit to being intelligent?", its "are the benefits of intelligence worth the cost?". For the mantelopes, who couldn't make tools and didn't need to think much to find food, the answer ended up being "no".
  • There are koalas in real life which evolved to be incredibly un-intelligent (to the point where they can no longer recognize eucalyptus leaves as food when plucked off a branch and put in a bowl. Apparently this is due to eucalyptus leaves being incredibly non-nutritive and the koalas who specialized to eat it were forced to evolve smaller brains to sustain this diet, so perhaps something similar happened to the Mantelopes?
  • What do the Mantelopes have to be intelligent for? They don't hunt prey, but do they have predators they have to think to avoid?
  • It's essential to remember that the Mantelopes are also horribly depressed and in intense pain from the awareness of their situation. Given how chronically miserable their existence is, It's likely that many Mantelopes tried and succeeded to kill themselves to put themselves out of their misery, or, at the very least, lacked the drive needed to continue living and either starved to death or just let predators kill them. It's inherently against most animals' instincts to not care about their own survival. Since the sole cause of this suffering is the Mantelopes' sapience, after a while, their intelligence would be a liability, as it prevents them from doing all of the things that all other species do, like reproducing, hunting, fleeing, and relaxing. At least in the short term, sapience doesn't serve the Mantelopes any purpose aside from stress. The Author even cites it as a mercy.
  • Intelligence is complicated and not just on a simple sliding scale. It's possible the Mantelopes were created with already-altered mental capacities. If for example they were too territorial to be comfortable standing close together, they would struggle to cooperate well enough to use their mouths as hands and jointly make and use tools. If they loathed each other, either out of territoriality or because they found themselves to be abominations, and their culture was built around songs of regret and defeatism, it would be harder for them to come together and form an enduring people.
• The Bone Crushers are said to communicate by deficating on each other, how exactly does that work? Many animals will use their urine and feces in communication but only in conjunction with other methods, typically things like marking their territory or to signal reproductive readiness. I'm not sure it's possible to convey complex information using dung, now would they be able to produce enough for these messages as they were able to reach a medieval level society before dying out, which would require a significant level of organization just to reach that point.
  • It never said that was their sole means of communication, only that they expressed affection by doing it.
  • Perhaps its like Morse Code, and the number of turds a Bone Crusher shits out holds some significant meaning? Or they can poop out certain shapes?

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