Line art time
Time for a bit of line art. This is an illustration from an ongoing personal project. The Ash Lizards (not what they call themselves, their actual name being physically-unpronounceable by anything with a human larynx/jaw) are intended as one of the more “familiar” alien species from Out of Place. They’re arguably just barely something that could have evolved here on Earth, although even then, there is some serious weirdness.
As I was working out their background, I found that they got stranger and stranger. So … they originate on an exomoon of a tepid Jupiter, which in turn orbits an M-type dwarf star. The moon, Keleck, is tide-looked, but its orbit still gives it a day-night cycle. The Jupiter actually orbits a bit too close to its star, so Keleck is actually hotter than Earth, averaging 40°C across its surface. Consequently, endothermy never evolved – there was just no point. (Also the tropical belt is a mix of deserts and salt flats, as it’s too hot for either C3 or C4 photosynthesis, or for that matter stable bodies of water.)
So, the Ash Lizards are exotherms. Their natural diurnal cycle involves basking to absorb heat; to speed this up they actually change colour over the day. In the morning they’re almost coal black; by mid-afternoon they’re bone white. This also helps them regulate their core temperature during the day – afternoons on Keleck can be rather warm. They darken again as the evening wears on, to absorb as much heat from the sun as they can.
(Completely pale skin is OK, as an M dwarf sun means that solar UV is a non-issue, incidentally.)
The tail is prehensile, and acts as a counterweight to the canted-forward fore-body. The Lizards are evolved from something resembling a reptilian kangaroo; they’re about as good at high-speed jumping as we are at climbing trees.
The backward-facing horns are an adaptation to a common Keleckian predator attack-strategy (striking from behind is harder when there are pointy bits there to headbutt with).
But the highest weirdness comes from Ash Lizard reproduction.
Keleck is a fairly barren and resource-poor homeworld. Consequently, prehistoric food supplies were quite limited. Maintaining a human-style always-on reproductive system was simply too expensive in metabolic terms. (Plus it would also risk dangerous population explosions, which could be guaranteed to turn into crashes very quickly.) So, they don’t do this.
Instead, the Lizards only become fertile when a sustained food surplus is available. Consequently, they have three sexes – male, female and neither, and Lizards will spend most of their lives as ‘neither’. In addition, when they actually are fertile, they can be either male or female, and a past sex is no guide to what the next one will be. (The gender split is decided amongst a population by a process of pheromonal negotiation.)
Reproduction is by laying clutches of eggs. Whilst hatching grounds as a whole will be protected, individual hatchlings were largely expected to look after themselves. Ash Lizards have no strong nurturing instincts, and there is no equivalent to the nuclear family in their social structure.
(I went with this as I’ve discovered that a) I’m getting bored of ‘aliens’ who just recapitalute human social biology and b) it was an interesting exercise to figure out an alternate basis for a social structure and what that other basis might imply.)
Here are a couple more pictures to give you an idea of the overall body type:
(Note that I’ve rethought the armour design in the above picture – the helmet in particular was just flat-out wrong, given the underlying anatomy.)