![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
camwynand because this morning I had a cup of Folgers mint mocha latte and two choco choco chip cookies (they were free), I have just spent some time running database queries and changes while composing more speculations about the two-legged riding animal. Specifically its evolution, which is my favourite part.
As far as I can tell, such a creature would almost certainly have to be a forest dweller, possibly in dense forests like the okapi. It's a browser that took to standing on its hind legs in order to get at decent leaves; longer-necked animals were able to reach even better leaves or leaves that hadn't been stripped bare by most of the other browsers, so they became the primary breeders of the original gene pool. The forelimbs were used for balance more often than not, but it was balance against the limbs of trees rather than the ground. I expect the animal is not hoofed after all, but has feet more like those of the forest horses in the original evolutionary bush of the Equidae. The tail of the original creature - and most of its relatives - was long and stiff a la that of the thylacine. I'm not sure what advantage a tail like that has to four-footers, but my beloved thylacines have them, so precedent exists. When the creature started employing both neck and hind limbs to get at accessible food, the tail became a counterbalance; when this became more common, the tail became a sort of secondary weapon against would-be attackers from behind, and the creatures with more mobile and heavy tails developed an evolutionary advantage. Of course, the heavy tail altered their balance somewhat, provoking changes in the muscular structure of hips and spine. Full upright posture was not as easy as one might hope, but massively muscular hips and an appropriately weight-bearing pelvis eventually developed even as the creature's forelimbs became less important. Grasping capability and good shoulder muscles, yes; running capability, no. The browser feet were extremely useful over uneven or mushy forest ground. Four limbs were not necessary for mobility.
The eventual result was an essentially two-legged creature that would give Moropus and the other chalicotheres a run for their money in the 'WTF did evolution DO?' department. The neck, while extremely long and mobile, is not as mobile as that of, say, swans. I expect it has somewhere between eight and fifteen, perhaps as high as twenty, cervical vertebrae. It's got a relatively small head, but the shock-absorbing system on the brain and spinal column is phenomenal. The ears are very large and extremely mobile; one would find similar ears on an okapi, I think. The eyes are large and situated more towards the front than on the sides, since head mobility is significant enough that seeing behind is not as much of an issue as one might think. Lips are of the split variety, like the living members of the Camelidae. The best word to describe those lips is 'prehensile'. There are incisors, although they are not as necessary as they might be thanks to the amazing leaf-ripping capabilities of those lips; there are molars, with the wrinkly surface design one finds in creatures like bison who must grind their grass on a regular basis. Big gap between the two. Decent sense of smell, though nothing spectacular. This is at least in part due to the narrow snout found on most browsing ungulates.
The forelimbs are structured not unlike kangaroo arms, although the paws themselves are different. The creature is descended from the equivalent of the anchitheres, I think. Four toes on the front feet, three toes behind; its hoofs, like those of the rock hyrax and the manatee, are nail-hoofs - at least in front. The fourth toe in front is not opposable, but the individual toes are spreadable and flexible to a significant degree, so it can grasp a wider variety of trees with relative ease. The forelimbs are carried close to the body when not in use, pulled up under the chest with the toes curled close like a bird standing on one leg. They are too short to be of any use in running, but can be used for scratching areas not quite reachable by the head.
You really and truly do not want to get in the way of the hind legs. The animal's pelvis is broad enough to accommodate live birth - I'm pretty sure this is a mammal, rather than a warm-blooded reptile, but even Apatosaurus had a pelvic opening big enough to pass a VW Bug. The vertebrae in this region are very thick, as they have to anchor the tail and the hip muscles; the Empire's engineers would do well to look this thing over before designing the next AT-ST model. The hip-and-thigh arrangement is probably closer to that of T. rex and the various allosaurs than that of kangaroos, if only because the dinosaurs ran on their two feet rather than hopped. I would need a closer look at the hip design of the ostrich before I could say for sure if there was a resemblance; that's one big egg they have to pass. Frankly, the design of the hip area is probably the most important element of the creature, because putting a rider on something with two legs seriously alters the center of gravity. The saddles almost certainly have to have two cinches, one in front of the leg and one behind - perhaps a crupper is mandatory as well, around the tail. Riders are simply going to have to position themselves almost directly over the hips if they expect to get anywhere on this thing, so a livebearer is probably the best design since it permits for a wider distribution of the weight to begin with. The fact that it's not an entirely upright bipedal stance doesn't hurt much, either, since true bipedalism is an absolute horror when it comes to setting up the birth of particularly large live young.
Mind you, the young do not have to be all that large, since they are not being born with sizable brains. One or two offspring at a time - more likely one, as with most members of the Equidae, Bovidae, Giraffidae, etc. - should do. The point of most contention during a birth is the pelvis, not the head, and given that pelvic widening can probably be governed by hormones as the animal moves into sexual maturity, that's not so bad a problem. Births are generally conducted while the animal lies on the ground, and the offspring is capable of standing and nursing within minutes of birth - although, being wobbly, the little one often has to hold onto its mother's leg with those forepaws. The milk is of good quality, although probably not as outstanding as that seen among the running species of deer. Close, but not really up there with caribou milk. I expect that the young may have to be weaned using a certain amount of their mother's cud, since until they get to full size they have less choice in the way of nutrition from available leaves. That, or Momma pulls down the leaves and passes them to the youngling. Maturation is probably relatively rapid; I'm thinking something on the order of horses here, but I need to check the stats on the giraffids.
There is, of course, the question of horns. Giraffes have them; so do their forest cousins, the okapi. Kangaroos do not. I don't think any marsupials had horns, but I don't know for sure. Horses do not. T. rex had no horns, but did not need them, being a carnivore. I have yet to find a reference to true horns or antlers existing on carnivorous animals - narwhals don't count, that's a tooth gone mad - and believe me, I've been looking. Sivatherium, an ancient giraffid that may or may not have lasted into the days of the ancient Sumerians, had them. Indracotherium, the eighteen-foot rhino creature better known as Baluchitherium, did not. The tragulid deer do not have them, having, um, fangs instead. Well, no, not fangs. Tusks, sorry. Not sure about the diet of the tragulids, but they're the tiny little primitive deer that live in thick forests. Elephants have tusks as well, of course. . . Mind you, the neck makes a few things easier for our creature. Indracotherium could not have reached the surface of water at foot level given the length of its neck and legs. Either Indy had to kneel to get at water, or it had to wade in, or it had a trunk- and I do not think there is evidence for a trunk. This creature has a neck of sufficient length to reach the water by crouching and so does not need the elephant's accommodation. It does, however, need a nice system of valves in the neck blood vessels, and its oesophagus is probably something to be envied. Acid reflux? Past that epiglottis and pyloric (I think) sphincter? I don't think so.
The creature sleeps lying down. It simply does not have the locking mechanism in the legs that allows horses to sleep standing up. The neck probably curls back on the body, placing the head on or near the animal's back while it sleeps. I would have to examine the feet on T. rex and its kin to see how the creature managed to handle bipedal standing; digitigrade bipedalism is a bit of a pain without accommodations in the knees or hocks to keep the creature upright. (Someone once complained about the design of most furries and invoked that as part of his argument.) I'm pretty sure our forest browser is digitigrade, but I'm not entirely sure. Having a wide ball-of-the-foot area, with the heel having turned into the equivalent of a fetlock, might help, but it's primarily that 'reverse knee configuration' that causes the balance problems. Doesn't seem to have stopped T. rex, though. Kangaroos don't count because at full upright they're three-legged.
I'm pretty sure the coat is either mottled or striped. Forest ungulates tend to go in for camouflage, as do forest predators (hello, Mr. Jaguar!). The okapi has a partly solid body but stripes on the legs and in a few other places. The quagga was essentially a zebra that dwelled in and around forests, if I recall aright - I'd have to check again - and that was brown in part, but striped as well. Chevrotains, tragulids, and other small deer retain their spots. The forest and swamp deer of Asia retain their spots as well. There is, of course, the possibility of the sheer 'buh?' factor in coat design - here I am thinking of the Malaysian tapir, which is black in front and white behind and that's pretty much it. Of course, that's a rainforest creature, but that's not all that different from the environment of the okapi. . .
I'm going to break off there for the moment. It's almost lunchtime. Comments so far?
As far as I can tell, such a creature would almost certainly have to be a forest dweller, possibly in dense forests like the okapi. It's a browser that took to standing on its hind legs in order to get at decent leaves; longer-necked animals were able to reach even better leaves or leaves that hadn't been stripped bare by most of the other browsers, so they became the primary breeders of the original gene pool. The forelimbs were used for balance more often than not, but it was balance against the limbs of trees rather than the ground. I expect the animal is not hoofed after all, but has feet more like those of the forest horses in the original evolutionary bush of the Equidae. The tail of the original creature - and most of its relatives - was long and stiff a la that of the thylacine. I'm not sure what advantage a tail like that has to four-footers, but my beloved thylacines have them, so precedent exists. When the creature started employing both neck and hind limbs to get at accessible food, the tail became a counterbalance; when this became more common, the tail became a sort of secondary weapon against would-be attackers from behind, and the creatures with more mobile and heavy tails developed an evolutionary advantage. Of course, the heavy tail altered their balance somewhat, provoking changes in the muscular structure of hips and spine. Full upright posture was not as easy as one might hope, but massively muscular hips and an appropriately weight-bearing pelvis eventually developed even as the creature's forelimbs became less important. Grasping capability and good shoulder muscles, yes; running capability, no. The browser feet were extremely useful over uneven or mushy forest ground. Four limbs were not necessary for mobility.
The eventual result was an essentially two-legged creature that would give Moropus and the other chalicotheres a run for their money in the 'WTF did evolution DO?' department. The neck, while extremely long and mobile, is not as mobile as that of, say, swans. I expect it has somewhere between eight and fifteen, perhaps as high as twenty, cervical vertebrae. It's got a relatively small head, but the shock-absorbing system on the brain and spinal column is phenomenal. The ears are very large and extremely mobile; one would find similar ears on an okapi, I think. The eyes are large and situated more towards the front than on the sides, since head mobility is significant enough that seeing behind is not as much of an issue as one might think. Lips are of the split variety, like the living members of the Camelidae. The best word to describe those lips is 'prehensile'. There are incisors, although they are not as necessary as they might be thanks to the amazing leaf-ripping capabilities of those lips; there are molars, with the wrinkly surface design one finds in creatures like bison who must grind their grass on a regular basis. Big gap between the two. Decent sense of smell, though nothing spectacular. This is at least in part due to the narrow snout found on most browsing ungulates.
The forelimbs are structured not unlike kangaroo arms, although the paws themselves are different. The creature is descended from the equivalent of the anchitheres, I think. Four toes on the front feet, three toes behind; its hoofs, like those of the rock hyrax and the manatee, are nail-hoofs - at least in front. The fourth toe in front is not opposable, but the individual toes are spreadable and flexible to a significant degree, so it can grasp a wider variety of trees with relative ease. The forelimbs are carried close to the body when not in use, pulled up under the chest with the toes curled close like a bird standing on one leg. They are too short to be of any use in running, but can be used for scratching areas not quite reachable by the head.
You really and truly do not want to get in the way of the hind legs. The animal's pelvis is broad enough to accommodate live birth - I'm pretty sure this is a mammal, rather than a warm-blooded reptile, but even Apatosaurus had a pelvic opening big enough to pass a VW Bug. The vertebrae in this region are very thick, as they have to anchor the tail and the hip muscles; the Empire's engineers would do well to look this thing over before designing the next AT-ST model. The hip-and-thigh arrangement is probably closer to that of T. rex and the various allosaurs than that of kangaroos, if only because the dinosaurs ran on their two feet rather than hopped. I would need a closer look at the hip design of the ostrich before I could say for sure if there was a resemblance; that's one big egg they have to pass. Frankly, the design of the hip area is probably the most important element of the creature, because putting a rider on something with two legs seriously alters the center of gravity. The saddles almost certainly have to have two cinches, one in front of the leg and one behind - perhaps a crupper is mandatory as well, around the tail. Riders are simply going to have to position themselves almost directly over the hips if they expect to get anywhere on this thing, so a livebearer is probably the best design since it permits for a wider distribution of the weight to begin with. The fact that it's not an entirely upright bipedal stance doesn't hurt much, either, since true bipedalism is an absolute horror when it comes to setting up the birth of particularly large live young.
Mind you, the young do not have to be all that large, since they are not being born with sizable brains. One or two offspring at a time - more likely one, as with most members of the Equidae, Bovidae, Giraffidae, etc. - should do. The point of most contention during a birth is the pelvis, not the head, and given that pelvic widening can probably be governed by hormones as the animal moves into sexual maturity, that's not so bad a problem. Births are generally conducted while the animal lies on the ground, and the offspring is capable of standing and nursing within minutes of birth - although, being wobbly, the little one often has to hold onto its mother's leg with those forepaws. The milk is of good quality, although probably not as outstanding as that seen among the running species of deer. Close, but not really up there with caribou milk. I expect that the young may have to be weaned using a certain amount of their mother's cud, since until they get to full size they have less choice in the way of nutrition from available leaves. That, or Momma pulls down the leaves and passes them to the youngling. Maturation is probably relatively rapid; I'm thinking something on the order of horses here, but I need to check the stats on the giraffids.
There is, of course, the question of horns. Giraffes have them; so do their forest cousins, the okapi. Kangaroos do not. I don't think any marsupials had horns, but I don't know for sure. Horses do not. T. rex had no horns, but did not need them, being a carnivore. I have yet to find a reference to true horns or antlers existing on carnivorous animals - narwhals don't count, that's a tooth gone mad - and believe me, I've been looking. Sivatherium, an ancient giraffid that may or may not have lasted into the days of the ancient Sumerians, had them. Indracotherium, the eighteen-foot rhino creature better known as Baluchitherium, did not. The tragulid deer do not have them, having, um, fangs instead. Well, no, not fangs. Tusks, sorry. Not sure about the diet of the tragulids, but they're the tiny little primitive deer that live in thick forests. Elephants have tusks as well, of course. . . Mind you, the neck makes a few things easier for our creature. Indracotherium could not have reached the surface of water at foot level given the length of its neck and legs. Either Indy had to kneel to get at water, or it had to wade in, or it had a trunk- and I do not think there is evidence for a trunk. This creature has a neck of sufficient length to reach the water by crouching and so does not need the elephant's accommodation. It does, however, need a nice system of valves in the neck blood vessels, and its oesophagus is probably something to be envied. Acid reflux? Past that epiglottis and pyloric (I think) sphincter? I don't think so.
The creature sleeps lying down. It simply does not have the locking mechanism in the legs that allows horses to sleep standing up. The neck probably curls back on the body, placing the head on or near the animal's back while it sleeps. I would have to examine the feet on T. rex and its kin to see how the creature managed to handle bipedal standing; digitigrade bipedalism is a bit of a pain without accommodations in the knees or hocks to keep the creature upright. (Someone once complained about the design of most furries and invoked that as part of his argument.) I'm pretty sure our forest browser is digitigrade, but I'm not entirely sure. Having a wide ball-of-the-foot area, with the heel having turned into the equivalent of a fetlock, might help, but it's primarily that 'reverse knee configuration' that causes the balance problems. Doesn't seem to have stopped T. rex, though. Kangaroos don't count because at full upright they're three-legged.
I'm pretty sure the coat is either mottled or striped. Forest ungulates tend to go in for camouflage, as do forest predators (hello, Mr. Jaguar!). The okapi has a partly solid body but stripes on the legs and in a few other places. The quagga was essentially a zebra that dwelled in and around forests, if I recall aright - I'd have to check again - and that was brown in part, but striped as well. Chevrotains, tragulids, and other small deer retain their spots. The forest and swamp deer of Asia retain their spots as well. There is, of course, the possibility of the sheer 'buh?' factor in coat design - here I am thinking of the Malaysian tapir, which is black in front and white behind and that's pretty much it. Of course, that's a rainforest creature, but that's not all that different from the environment of the okapi. . .
I'm going to break off there for the moment. It's almost lunchtime. Comments so far?
