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Post by Exalt on Nov 27, 2023 7:11:13 GMT 5
I'm confused. The 30mm vertical lines on each side are clearly not the same length. The ones on the bones themselves seem helpful, otherwise.
Also, I forgot to mention this, but I apparently mentally oversized Jaguars coming into this.
EDIT: While I have heard of Smilodon having thick forelimb bones, why does that help? Is it as simple as more and/or denser muscle being able to attach to it?
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Post by Infinity Blade on Nov 27, 2023 10:20:37 GMT 5
The scale bars are different because the bones are not the same size. The fact that 30 mm is shorter relative to the Smilodon’s humerus means that its arm bone is overall bigger than the jaguar’s.
The thicker cortical bone simply means it’s a lot stronger and won’t break as easily to bending stresses when wrestling against prey.
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Post by mechafire on Nov 28, 2023 14:49:31 GMT 5
What post-cranial remains do scientists have of Equus giganteus and do they support its massive size estimates?
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Post by Infinity Blade on Nov 28, 2023 21:29:21 GMT 5
What post-cranial remains do scientists have of Equus giganteus and do they support its massive size estimates? We don't actually have any postcranial remains from Equus giganteus. The species is based on a single tooth described in 1901, with its great size apparently being the most notable thing about it (although, it was distinguishable from E. crenidens). This tooth was stated to have had a diameter exceeding that of the largest modern draught horses by more than a third ( Gidley, 1901). So unfortunately the only thing we have to go off of to estimate its size is the tooth. It was said to be a second molar, and assuming that's true, the estimated mass would be ~1,600 kg. However, it's also possible it was a premolar. Assuming it was a P4, the body mass would turn out at ~1,250 kg. Assuming it was a P3, ~1,320 kg ( Eisenmann, 2003). So in short, we still only have the tooth to go by. But for whatever it's worth it does suggest pretty large sizes no matter how you slice it. |
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Post by Exalt on Nov 29, 2023 8:37:18 GMT 5
So believe it or not, I have another glyptodont topic.
How would predators attack them, and how would they defend themselves?
Prehistoric Predators and Life On Our Planet both suggested that the young, at least, could be flipped over. There is apparently evidence that Smilodon predated upon them, but I'm not sure the age. I am guessing the most obvious spot of attack for them, and possibly jaguars, would be the head, but I'm not sure how they would go about it. (I think I was discussing with people about a glyptodont skull pierced by one of the two, but this has been awhile.) I would think that the nature of the glyptodonts back would make jumping on top of it and going for vitals would be very difficult, unless the felids in question were to employ their flexibility to attack the head from this position, but that feels difficult to imagine.
Perhaps some of the larger species would be "immune" to predation as adults, barring the head. I would think that even A.angustidens would need to be cautious regarding some of them. Now, would glyptodonts be headbutting their assailaints, or what? It seems debated how well Doedicurus could actually use it's tail club, though estimates suggest that it could at least be swung at high speeds.
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Post by mechafire on Nov 29, 2023 11:14:28 GMT 5
So believe it or not, I have another glyptodont topic. How would predators attack them, and how would they defend themselves? Prehistoric Predators and Life On Our Planet both suggested that the young, at least, could be flipped over. There is apparently evidence that Smilodon predated upon them, but I'm not sure the age. I am guessing the most obvious spot of attack for them, and possibly jaguars, would be the head, but I'm not sure how they would go about it. (I think I was discussing with people about a glyptodont skull pierced by one of the two, but this has been awhile.) I would think that the nature of the glyptodonts back would make jumping on top of it and going for vitals would be very difficult, unless the felids in question were to employ their flexibility to attack the head from this position, but that feels difficult to imagine. Perhaps some of the larger species would be "immune" to predation as adults, barring the head. I would think that even A.angustidens would need to be cautious regarding some of them. Now, would glyptodonts be headbutting their assailaints, or what? It seems debated how well Doedicurus could actually use it's tail club, though estimates suggest that it could at least be swung at high speeds. Sorry, don't know how to resize images. Here's just an example from a source Infinity Blade shared. it's a juvenile Glyptotherium texanum skull with puncture marks caused by a carnivore, perhaps Smilodon gracilis.  Source: Gillette et al. 1981 Glyptodonts of North America DOI: doi.org/10.5479/si.00810266.40.1 |
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Post by mechafire on Nov 29, 2023 11:20:57 GMT 5
What post-cranial remains do scientists have of Equus giganteus and do they support its massive size estimates? We don't actually have any postcranial remains from Equus giganteus. The species is based on a single tooth described in 1901, with its great size apparently being the most notable thing about it (although, it was distinguishable from E. crenidens). This tooth was stated to have had a diameter exceeding that of the largest modern draught horses by more than a third ( Gidley, 1901). So unfortunately the only thing we have to go off of to estimate its size is the tooth. It was said to be a second molar, and assuming that's true, the estimated mass would be ~1,600 kg. However, it's also possible it was a premolar. Assuming it was a P4, the body mass would turn out at ~1,250 kg. Assuming it was a P3, ~1,320 kg ( Eisenmann, 2003). So in short, we still only have the tooth to go by. But for whatever it's worth it does suggest pretty large sizes no matter how you slice it. Yeah. This is what I believed as well. I read somewhere E. giganteus was described, and had its size estimates, based on a tooth, but there are other remains. I guess not. Unless there are parts of skulls. It's kinda like a Gigantopithecus situation. |
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Post by Infinity Blade on Nov 30, 2023 3:19:54 GMT 5
So believe it or not, I have another glyptodont topic. How would predators attack them, and how would they defend themselves? Prehistoric Predators and Life On Our Planet both suggested that the young, at least, could be flipped over. There is apparently evidence that Smilodon predated upon them, but I'm not sure the age. I am guessing the most obvious spot of attack for them, and possibly jaguars, would be the head, but I'm not sure how they would go about it. (I think I was discussing with people about a glyptodont skull pierced by one of the two, but this has been awhile.) I would think that the nature of the glyptodonts back would make jumping on top of it and going for vitals would be very difficult, unless the felids in question were to employ their flexibility to attack the head from this position, but that feels difficult to imagine. Perhaps some of the larger species would be "immune" to predation as adults, barring the head. I would think that even A.angustidens would need to be cautious regarding some of them. Now, would glyptodonts be headbutting their assailaints, or what? It seems debated how well Doedicurus could actually use it's tail club, though estimates suggest that it could at least be swung at high speeds. So, the Glyptotherium that was preyed on by a cat (pictured in mechafire's post) was a juvenile. Not only did this mean that the head shield on it wasn't fully developed (as it would be in an adult), but also the angle of the bite marks suggests that the cat attacked from the front. A glyptodont would probably want to keep its head away from a predator, so the fact that this one didn't led the author to suggest that it was stranded in mud or something. In short, this glyptodont was made more vulnerable to predation by two things: 1) it was young, 2) it was probably immobilized. An adult glyptodont should be okay relying on its armor as passive defense, if nothing else. Headbutting with those armored robust skulls, or even shoulder shoving/wrestling, sound like intriguing methods of combat, although I'm not sure if that's going to be so effective on a much smaller, more agile predator (in most cases, anyway). |
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Post by Exalt on Nov 30, 2023 5:55:29 GMT 5
So what would they do with their head normally, then?
EDIT: I just remembered another question I had in mind. Does cannibalism ever have a meaningful impact on a species survival and/or population?
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Post by Exalt on Nov 30, 2023 21:56:01 GMT 5
Why do tigers do well in both hot and cold environments? My guesses are:
-differentiation in the subspecies
-felid (or even feliform) adaptability, since lions and hyenas can apparently grow more fur in cold conditions
I think I had a third, but if so, I have forgotten.
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Post by Infinity Blade on Dec 1, 2023 5:07:03 GMT 5
Why do tigers do well in both hot and cold environments? My guesses are: -differentiation in the subspecies -felid (or even feliform) adaptability, since lions and hyenas can apparently grow more fur in cold conditions I think I had a third, but if so, I have forgotten. They must have enough genetic variation in their gene pool to have adaptations like shorter or thicker fur for different environments. As for why they do, I don't think there's any real answer to that, they just...do. |
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Post by Exalt on Dec 1, 2023 5:13:00 GMT 5
Tigers: they just do.
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Post by theropod on Dec 1, 2023 21:44:31 GMT 5
Why do tigers do well in both hot and cold environments? My guesses are: -differentiation in the subspecies If there was no differentiation, then they wouldn’t be subspecies. I don’t think there’s anything particular to felids or feliforms about that. Pretty much any animal with fur will be selected for more of it in colder climate zones, and a lot of mammals in cold climates tend to grow thicker fur in winter. Look at the geographic ranges of some other animals. There are brown bears in Alaska, Siberia and Scandinavia, but also in Greece, Turkey and Iran. There are grey wolves in all of those places, as well as India and Arabia. |
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Post by Exalt on Dec 1, 2023 23:52:02 GMT 5
Perhaps I thought too small, then, particularly given that the rise of mammals is associated in part with their ability to withstand cold temperatures better than reptiles.
I did not know that brown bears and grey wolves were in the warmer places listed.
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Post by Exalt on Dec 5, 2023 10:32:41 GMT 5
Why did primates evolve flatter faces and firward-facing eyes?
Edit: additionally, why might leopard seals have evolved to have larger females than males, when other pinnipeds, and many carnivorans, many mammals in general, really are much more inclined to have larger males? I'd ask about hyenas too but I'm not sure about their closest relatives.
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