"The Alinrae were a space-born civilization, who were incredibly tall. When they arrived on Kalrania, they had to adapt to the higher gravity, and as a result, they became shorter - more compact and muscular. After several generations, the first formally known 'Raenum' was born. The traits that the Raenum evolved from their environment are;

  • Colored Skin, the color derived from that of the first plant the individual ingests.

  • Stronger Muscles, built in their arms and legs, and somewhat in their core, which came from the need to rip their food out of the ground or rip their food apart

  • UV-absorbing (Radiation Resistant) Skin, as they were an originally space-born species - which facilitated the need to better withstand radiation - as well as the desert and hot climate of Early and Present Alingarch"

What I am wondering, is how plausible the species as a whole is? For the parts that aren't plausible - how might I fix it?

  • 6
    $\begingroup$ well, the colored skin of first thing they eat would be tricky $\endgroup$
    – Topcode
    Sep 16, 2020 at 22:13
  • $\begingroup$ To clarify - the skin color is by individual (what that person ate) not collectively (this is the color of the first major foodstuff the species consumed). Otherwise, nothing is odd in any of these, except that these traits would take more than a few generations to develop. The genotypes would already need to exist, but expression would need to change due to environment. $\endgroup$
    – DWKraus
    Sep 16, 2020 at 23:30
  • 2
    $\begingroup$ Is that 'space-borne' as in they travel through space or 'space-born' as in they came from space? Because an intelligent species evolving in space itself isn't really plausible to begin with. $\endgroup$
    – Halfthawed
    Sep 17, 2020 at 12:05
  • $\begingroup$ This isn't long enough for evolution to work its magic. Though I think that the stronger muscles could occur just because they have to do hard work to move, as opposed to micro-gravity. $\endgroup$
    – NomadMaker
    Jun 4, 2021 at 19:08

2 Answers 2


Colored Skin, the color derived from that of the first plant the individual ingests.

Easiest part, certain chemicals in plants trigger hormonal reactions, once reaction is triggered it is impossible to stop it (feedback loop) at least not without advanced medical tech. Different hormones activate different pigment synthesizing cells to varying levels. Think natural CMYK or RGB if color comes from luminiscence.

Stronger Muscles

Compared to humans chimps have way more strength for same volume and weight of the muscle, at the cost of endurance and stamina, do same correlation for your species. Their muscles are optimized for the short bursts of heavy work at cost of getting tired faster.

UV-absorbing(Radiation Resistant) Skin

They secrete natural sunscreen not unlike hippopotamuses.

Most of these qualities already exist naturally except first, but there are animals capable of changing color on varying timescales, you just need permanent version.


Very Plausible with Some Plot Holes

What's Missing:

To justify the "space-born" paradox, there may have to be an artificial origin story... perhaps the recombinant genetic engineering of two similar species of intelligent life (with artificial factors that support long-term space travel). I suggest a weak artificial gravity environment, such as rotating stations for the space-born variety. This would imply that they could potentially adapt to gravity, but would be at a disadvantage in doing so (thus creating increased evolutionary pressure for divergence into another species).

Colored Skin:

I assume that this is similar to flamingos. For mammals, there is no noted example. Either the substances in the foods survive digestion and color the blood and embedded themselves in skin cells (similar to coloring cells for microscope slides, or the way toxins in certain bugs, frogs, and rare birds can accumulate), or your creature has scale-like skin (microscales like sharks perhaps) and the pigment becomes a part of this structure like the flamingo diet which turns their feathers pink.

Stronger Muscles:

The food in question may need to be described in detail. Like, why isn't digging it out of the ground an option? Is this a meat or vegetable, or some sort of plant-like animal (think anemone, but land-based)? Greater strength vs. the space cousin species is likely as gravitational impact creates stronger muscle, perhaps being a reversion to suppressed genes in the engineered species scenario. The hard part is finding a proper biological analogy. Gorillas have greater strength due to the need to bend branches to eat leaves. Baboons live in the savanna, however, and seem to use their relative strength to hunt other animals or defend against predators. The question of whether it is possible is "yes", muscles may pulse at a more frequent rate to generate greater strength capacity, or may be more dense. The real question is whether the evolutionary pressure is enough with ripping tough food being the primary reason. Perhaps adding a secondary reason (other than just the increased gravity) would help here.

UV Absorbing Skin

I assume a more pigmented thicker outer layer of skin would work for this. There are other solutions, but thicker skin would limit UV penetration to lower layers and with proper pigments the UV resistance is increased.


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