First, I'm contributing by helping to understand the hypothetical anatomy of reptilian humanoids (reptilian, reptoid, draco, whatever), in order to
see if it would be physically possible for such creatures to have evolved on Earth. I'm trying to analyze probable paths of reptilian evolution that
could have, theoretically, lead to the existance of a sentient, "humanoid" saurian species.
Here's a list of traits and notes about anatomy I put together (so far) that I think should be taken into consideration. I made this list by
observing and comparing characteristics found in humans, dinosaurs, birds, and various reptiles (and careful observation of myself in the mirror). I
think these traits are very important and could possibly be deciding factors in determining whether it is physiologically prossible for a reptoid
(humanoid reptilian) species to exist.
For a reptile to appear humanoid, I believe it may just require some of the same choices in natural selection, sexual selection, and (oddly) domestic
selection that we made in our own evolution. There are plenty of animals that look similar, have similar traits, and perform similar functions, but
are completely different species (take birds and bats, for example). In theory, it's not entirely impossible
that a reptoid could exist.
What we should probably look at is not the possibility
of reptoids existing, but the probability
of reptoids existing.
The following traits may not be completely essential for a humanoid reptile to exist, but they would have needed to develop some sort of alternative
equivalent (in the same way that bats don't need feathers in order to fly, instead having webbed skin between digits).
- In humans, the pelvic bone bares the weight of our internal organs. It does this by forming a semi-"bowl" shape that cups the
lower organs near our hips. In quadrapedal animals you'll notice that the internal organs are supported by the ribs, not the hips. The same is true
in all other known
bipedal animals, such as birds and dinosaurs... Although they are obviously standing on two legs, they are not standing
pelvis_male_anterior_PB121176.JPG - Male hip, front.
pelvis_male_superior_PB121177.JPG - Male hip, above.
pelvis_female_anterior_PB121174.JPG - Female hip, front.
pelvis_female_superior_PB121175.JPG - Female hip, above.
If you're a supporter of the "Reptoids evolved from dinosaurs" theory, reptiles would had to have evolved mammal type hips, then evolve a hip that
would form an appropriate shape for supporting their organs. Otherwise, they would not be capable of standing truly
upright, only at a
, probably somewhere between 45 and 90 degrees. If you look, you'll notice illustrations of dinosaurs, such as Iguanodons,
standing semi-upright. However, these pictures are somewhat misleading. Their normal posture would be more horizontal, and would probably only stand
semi-vertically for brief moments, such as when reaching for food from high places.
- Notice the awkward way this skeleton is positioned. It looks off-balanced. This Iguanodon would
not be able to stand like this for long, much less actually walk like this. The torso is too bulky and heavy. (Add: torso of dinosaurs would need to
- The size of female hips would depend on the amount of space needed for the birth canal. If females give live birth like humans,
they would look similar to human females in shape (i.e. wide hip, hour glass shape). However, if they lay eggs, like most known reptiles, the birth
canal would be significantly smaller, meaning that the difference between the shapes of male and female hips would differ very little, if at all.
- Note the difference between male and female hips in humans.
Male and female sizes
- Many paleontologists, based on dinosaur skeletons and clues from modern birds and reptiles, believe that some dinosaur
species (such as Tyrannosaurus) may have had larger females than males. Just something to think about. (Has anyone run across stories of female
reptoids in abduction cases?)
& Standing on toes vs. heels
- Because of our vertical posture, humans center their body-weight with their legs. So to take some
of the stress of weight off our leg muscles, we've developed knee bones that prevent our legs from bending backwards. Because of this, we can keep
our legs straight and balance our weight on our legs much easier, as if being supported by straight poles.
When looking at skeletons or illustrations of bipedal dinosaurs, you can see that they're shown standing on their toes, instead of their heels as
- Leg bones of a Utahraptor. Notice that the heel is raised and forms a sort of reverse
knee-type joint, instead of a structure for standing on.
You might notice that if you stand on the tips of your toes that you automatically tilt the rest of your body slightly forward in order to
counterbalance the backward push of your toes. This is an awkward position for a person to stand. Now, if you bend your knees some, you'll notice
that your back will straighten again (assuming you have a straight posture to begin with).
If a humanoid reptile were to stand upright it would either have to stand on its toes with bent knees, or evolve to stand on its heels with straight
knees. Upright posture means that more of the body's weight is focued into a smaller surface area on the ground, instead of being spread out and
balanced. If standing on its toes, this would mean it would be in a constant state of holding its full weight up with its leg muscles, resulting in
either extremely powerful leg muscles, or the creature becoming easily fatigued after extended periods of movement (definitely not an evolutionary
(Add: also, heels have sponge-like bones for shock absorbance. I don't know if dinosaurs toes are formed like this, but reptoid heels would need to
be, if they walk on heels)
I'll post again after more research and typing.
[edit on 21-12-2005 by CloudlessKnight]