My question is basically about what a gliding mammal that can magically produce thrust would look like, whilst meeting these criteria:
- Can use tools to a sufficient level to develop civilisation
- Is adapted to life in the mountains
- Its gliding ability is useful for life in the mountains (this is perhaps more related to the amount of thrust it can produce and for how long, but the skin flap design also plays a part)
In the fantasy world I am working on, plants and non-human animals will sometimes develop "magical" adaptations. These will develop similar to evolution where a magically ability will sometimes randomly develop, and can be passed on to offspring. Magical abilities require higher energy use but not necessarily proportional to the amount of energy the physics of the ability requires. For that reason a "useless" ability is unlikely to become pervalent.
I am working on a gliding mammal that has developed some kind of limited ability to produce thrust and has a similar intelligence to humans.
For the sake of argument let's say they can produce a jet in a direction they choose for a limited amount of time per day. Let's say the jet produces a maximum thrust of 0.2 times their body weight, but add the limitation that using the jet at maximum force is strenuous so they would be able to do it for a shorter time.
I am open to other forms of generating thrust if you think they would work better.
Gliding seems to be a common adaptation that has independently developed many times. In mammals, this adaptation seems to develop in arboreal animals. A possible evolutionary explanation for this evolution is energy efficiency when gliding. Another possible explanation is the ability to avoid predators. It seems to make sense to say that this sapient gliding mammal evolved from some kind of arboreal glider before developing powered flight through their jet ability, allowing their ancestors to live in more mountainous regions over time. Another possibility is that the jet ability developed first in some mountain primate, rodent, or marsupial before the gliding membranes evolved. The jet ability may have been selected for to allow for better jumping.
A common feature of these gliding mammals, as far as I can tell, is that they are bad at locomotion compared to their brethren who have no patagium.
The colugo is supposedly the best adapted glider, so it seems like a useful reference to use. According to Wikipedia, they reach lengths of 35 to 40 cm (14 to 16 in) and weigh 1 to 2 kg (2.2 to 4.4 lb).
Wingsuits may also be a useful reference. The electric wingsuit developed by BMW might be a good illustration of the physics involved. The device puts out 20hp for around 5 minutes, but I am not sure how those numbers relate to my earlier suppositions about the creature's jet ability.
I am not particularly attached to any of these ideas, but they are the ideas I have reached after my research and hopefully they provide a good starting point.
- Height and weight: The creature is 1 - 1.2m and weighs 15-18kg. The greater height should be useful for agriculture and animal husbandry, whilst the higher density allows for a sturdier creature design with potentially better locomotion. Given how humans can fly with a powered wingsuit I think this creature's density could be even higher if that is useful.
- Hands: The hands have opposable thumbs and are webbed. Potentially the thumb isn't webbed for better dexterity. The webbing is a feature colugos have and seems to be useful for gliding. Their hands are likely relatively larger than a colugo's hand, for better tool use. I am not sure if this creates issues for flight, since flying squirrels supposedly have smaller hands to avoid "wing loading", but I hope the webbing and jet ability will offset any issues. The hands potentially have small vestigial claws from their arboreal ancestors.
- Legs and feet: Unlike all flying mammals I have found in my research, this creature's legs are not attached to the gliding membrane. This allows for better locomotion, bipedalism, and the ability to ride animals. I envisioned the feet as capable of gripping, similar to an eagle's claw. This is for two reasons: first I imagined that their evolutionary ancestors used their flight ability to swoop in and grab eggs or small animals with their feet as birds do. The second reason is for gripping the ground so they are not blown away by the winds at high altitudes. The legs and feet I imagined are part of the reason I gave them a higher density than colugos.
- Gliding membrane: also known as patagium. This is one of the parts I am very iffy about but I will mention my current thoughts. To make up for the membrane not being attached to the legs I imagined it going from the wrists to a bifurcated, or trifurcated, tail. There would also be a membrane in between the tail parts. My main concern is having sufficient arm mobility for tool use whilst still having enough membrane for useful gliding. Arm mobility could potentially improve if the membrane is attached to the elbows.
- Tail: As mentioned above I imagine it as being bifurcated or trifurcated. This would, in theory, allow for sufficient membrane whilst allowing the legs to be detached. I also imagine that the tail can be moved in such a way that the membrane attached to the wrist is loose enough to give the arms a good amount of mobility.