The classic image of the angel is a winged humanoid superior to humans in power and intelligence. How do we make this biologically real?
For starters, no wings anchored to the shoulders! Finding an evolutionary justification for this is a massive headache. Besides, it's also a cliche unto itself.
My first proposal is that there are actually two major groups of angels--the "common angels", inspired by both bats and pterosaurs; and the "classic angels", inspired not by modern birds, but by the "four-winged dinosaur".
But before we differentiate the two groups, let me list my proposals on how alike they are:
- Tetrachromacy--all mythological humanoids have a fourth color receptor, which allows them to see colors beyond the visible spectrum.
- Respiration--all mythological humanoids have lungs taking up 15% of their overall body volume, rather than the typical mammalian 7%. In both angels, air sacs are added so that they can both breathe and cool down more efficiently.
- Circulation--all mythological humanoids have hearts so large that if they were human, they would be diagnosed with the condition called "cardiomegaly".
- Chest--both angels have an enlarged sternum, or "keel", equal in size proportion to a pigeon's (by itself, proportionately larger than a raptor's) for maximum takeoff strength.
- Legs--in proportion to length, both angels have human legs, but human legbones are thick and wide, so my proposal is to narrow them down so that they are more gibbon-like than human-like.
- Abdomen--the previous proposal applies to the ribcage as well, thus allowing the bulk of the musculature to be focused on the chest and arms, crucial for flight.
- Bones--obviously, hollow bones help reduce the body's weight without sacrificing its strength, another cruciality for flight.
- Brain--both angels have proportionately larger brains than ours. For example, the common angels have a cranial area averaging 1720 cubic centimeters. In both angels, the flocculus, a region that integrates signals from joints, muscles, skin and balance organs, makes up 2% of the total brain mass. (I was originally going to propose raising the percentage to 7.5%, so it can be more pterosaur-like, but recent science has proposed a potential relationship between flocculus size and behavior complexity.)
- Arms--in proportion to body size, the humerus, radius and ulna are all gibbon-length, not human-length (17% of overall body length, rather than our 11%). The hand is still human-like, though instead of nails, they'd have claws.
The differences between common and classic angels, though present, still don't hold a candle to the similarities. But propose them, I must.
The common angels still have their extra-long gibbon-arms, but if we compare their fingers to our own, we'd find that the common angel's ring fingers and pinkies have lengthened by 850%. Connecting them all the way down to their ankles are solid sheets of skin strengthened by actinofibrils, fibers spaced closely together. The wing membranes also contain a thin layer of muscle, fibrous tissue, and a unique, complex circulatory system of looping blood vessels, exactly like pterosaurs. Their whole bodies are covered not in regular mammalian fur, but pycnofibers, again like pterosaurs.
The classic angel, on the other hand, are coated in feathers. They have not the traditional two wings, but four, just like the ancient dinosaur Microraptor. They are also smaller--whereas the average male common angel is 5'2" in height, the average male classic angel is 5'0". (Females from both groups are 3/4 the male's size.)
Are any of my proposals listed above sound, or have I created some unintentional side effects to the angel bodies?
