Headscratchers / Serina

• The sawjaws are perfectly able to walk on their front legs alone, becoming bipeds and turning their hind leg, originally a tail, back into a tail again. So if this was a perfectly feasible solution, then why didn't the tribbets assume this body plan to begin with? Especially with all the mentions of the disadvantages of tripedal locomotion limiting their size and being less stable, it's not too far off to imagine some early tribbets would quickly have evolved to be bipeds and quickly gained the upper hand over the tripods.
• How come the thorngrazers are described as "a niche unlike any other"? Isn't grazer-scavenger just basically pigs?
  • Even with their numbers and defenses, pigs are still actively preyed upon and are somewhat selective in the types of matter they can eat. Their diet doesn't include a lot of grass or wood for example. Thorngrazers are much larger and are much harder to kill and are able to eat a lot more. A pig's niche is forager. A thorngrazer's niche is biological bulldozer.
  • The closest analogue would be ceratopsian dinosaurs and perhaps gastornithiformes and some kinds of multituberculates^note Specifically Meniscoessus, large djadochtatheroideans and gondwanatheres, all animals that rank as herbivores but have sawing jaws, nominally browsers with the equipment to process meat. However its unclear if they too were capable of surviving entirely on meat, something not possible for any known browser due to herbivory demmanding complex stomachs. The thorngrazers are the only animals capable of true omnivory without any compromises.
• How exactly did the knowledge that gravediggers were intelligent beings make the woodcrafters suddenly more open to them and reflecting on their actions? Given there was literally millions of years of war, you'd think the knowledge that the enemy is a thinking creature would only have led to even more fear, rather than sympathy and understanding.
  • They discovered gravedigger intelligence through their art, meaning they have direct evidence that they are feeling creatures outside of hunting with interpretations of the world. Also, at that point the gravediggers have long since stopped hunting the woodcrafters, the knowledge that they're sapient means that this was a deliberate choice on their part. It was a one-sided slaughter at that point, not a war.
• The boomsingers are taller than many sauropods and yet only weigh 15 tons? A sauropod of that similar size would weigh at least 50.
  • Likely a result of the moon's lower gravity compared to Earth.
• How do tribbetheres breathe with their nostrils, if their lungs evolved from offshoots of the stomach and fish nostrils are solely for olfactory purposes?
  • Fish actually have two connected pairs of nostrils, the anterior and posterior nostrils. In the ancestors of tetrapods, the posterior nostrils migrated inside of the mouth, allowing them to use their nasal cavity to breath. (Interesting side note: Human fetuses start out with four nostrils and recreate this transition as they develop.) Tribbetheres are depicted with only two nostrils, so it can be assumed they internalized their posterior nostrils at some point as well.
• It's mentioned that the tribbetheres are greatly constrained in size due to having three legs, which is why the largest land tribbethere, the Thorngrazer, only weighs 1,500 pounds (about the weight of an adult cow). However, it's shown to be just about pig-size (which is odd as Serina's gravity is lower than Earth).
  • It's mentioned in passing that the single hind leg supports the entire weight of the body for part of the walk cycle, though it doesn't seem improbable for a bigger, slower tribbethere to have a gait that only moves one leg at a time, with two legs on the ground at any given time.
• So Serina is a moon of a gas giant. So how does it stay habitable? If it's tidally-locked to the planet then wouldn't it follow a corkscrew-like pattern around the sun, thus producing massive fluctuations in temperature as well as an irregular day-night cycle? To say nothing of the planet's gravitational pull causing immense tides and tectonic activity, and the massive amounts of radiation reflected off the planet bombarding Serina...
  • Apparently Sheather has actually retconed the planet orbiting a gas giant and now it's just a standard planet. That's why you don't see the gas giant in the updated cover art.
• In nature, populations of animals are limited by food sources and pressure from predators and competitors. So when the initial wave of canaries was introduced to Serina, with limitless food and no predators, why didn't the infamous "invasive rabbits in Australia" scenario happen, with the canaries eating all the food, breeding at an extreme rate from lack of predators, and then quickly starving to death en masse once there is no food left, within the span of only several years or decades?
  • While we don't start seeing life on Serina till 10'000 years after the terraforming was finished, it can be assumed that something like this happened in the first few years but I doubt that would have killed all of them. Small populations likely survived and repopulated and by the 10'000 year mark they have reached some kind of equilibrium.
• How exactly do the tribbetheres expel waste? Do their intestines pass through the single hind leg, which would be a problem due to the leg joints getting in the way?
  • Word of God claims that the tribbethere anal opening is located on the belly, just in front of the hip joint of the hind leg.
• What advantage does the multiple-stage life cycle of the Ornimorphs grant them? Wouldn't it be inefficient to have to deal with so many different lifestyles before they can actually reproduce?
  • It's explained on their page that at their size the amount of time and nutrients they would need to make their mucus cocoon would have been even more inefficient. Plus, one should remember that nature doesn't always select for what's most efficient, sometimes it just settles for whatever happens to work at the time, even if it's somewhat impractical.
• Why were clovers and sunflowers placed on the planet without the appropriate insects? It's mentioned that the flowers placed on the moon went into a sharp decline due to a lack of of pollinating insects, so why include them at all if you aren't also going to include their means of reproduction?
  • It is likely that the vacancy of such a niche will promote natural selection by causing organisms to evolve to fill it, which has been done with the honey ants.

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