Neanderthal Cranial Features and Adaptations

And this is segment two of learning module 14. Okay, so we left off talking about Neanderthals and how their cranial features have the retention of some very primitive traits, such as having some large brow ridges. And in fact, there's a lot of volume to the top of the cranium, but there's still this sort of sloping part of the forehead. But now moving on to another distinctive feature of Neanderthals has to do with the occipital bone. So, If you recall, we're looking at the occipital bone is the bone in the back of the cranium, the top part, if you recall, is the sagittal bone, the sides of the parietals, and then the back is the occipital bone. And in Neanderthals, they actually have a part of the occipital bone that juts out in what's called an occipital bun. I guess this is sort of like an homage to what a woman's hair bun or something like that, right? But it's this bony bulge in the back of the cranium, and it looks like you kind of just punched out the back of the cranium a little bit here, and it sticks out. And in modern humans, we don't have that. We don't have that occipital bun. There is, of course, some evidence that modern humans as Homo sapiens, at the same time as Neanderthals about 100,000 years ago, did in fact have occipital buns. The movie that I'm asking you to see... Neanderthals on trial actually goes into more information about what the adaptive significance is of the occipital bun in Neanderthals versus what we see in modern humans, but this this occipital bun really is also sort of the artifact or the remnant of having a larger brain in which you would have expansion in the vertical part of the cranium and then also in the in the back and bottom part of the cranium so we see in In Neanderthals, it's very rounded on the bottom of the cranium. It's very similar to humans, much more so than Homo erectus or Heidelbergensis. If you recall, Homo erectus had very flat back here, had kind of a triangular-shaped cranium, and then very flat. And of course, if you go further back in time, early Homo or the Australopithecines had even more flat cranium. So with this encephalization, this increase in brain size, we get... this expansion in the lower part of the cranium. Furthermore, we get quite a lot of prognathism going on in Neanderthals. As I mentioned previously, a lot of that has to do with having a large nasal cavity and having large sinuses. And so overall, you see that the cranium of Neanderthals, it's ovular. It's sort of a football-type shape, longer cranium than you see with modern humans. Modern humans tend to have much more tucked in cranium. The face is kind of directly below the brain case, sort of a more globular type of shape. So if you do a side by side comparison, you can really see the major differences between Neanderthals and humans cranially. Here's a reconstruction of Homo Neanderthalensis. I love this one. I don't know why they always seem to give Neanderthals a slightly dumb look to them. I don't really know why. That large brain size certainly suggests that there's something going on there intelligence-wise. We're not entirely certain exactly how intelligent Neanderthals were. In some respects, at least culturally speaking, they have highly sophisticated tools, just like modern humans, and so that would suggest sort of equal human intelligence, but we don't find things like art with Neanderthals. We don't find them doing a lot of creative things. That seems to be sort of a distinct hallmark of modern human intelligence. But there's pretty good evidence that Neanderthals were very intelligent. Furthermore, I also have to point out that, of course, this is an artistic reconstruction that we can't know for certain how much body hair Neanderthals would have had. We can't tell the color of the skin. We can't tell things like the color of the eyes. They probably would have had larger noses because they do have larger nasal cavities. And they probably would have had quite a bit of prognathism because of these larger nasal cavities. So they would have looked different. They would have looked different than modern humans. But would a modern human really consider them to be not human is really ultimately the question. All right. So. Looking specifically at these cold weather adaptations that I've been referring to, we've talked about how Neanderthals have have this sort of robust muscular skeletal, yeah, skeletal, in which looking at some very stocky short limbs, now here's the cool part about short limbs, we see in modern human populations that are in very cold weather climates like the Inuit of Alaska and Canada, they tend to have shorter limbs than other human populations. And that has to do with the fact that you actually lose the most amount of body heat through your limbs. They are these extensions that take blood away from the core, and you lose a ton of body heat through your limbs. Having shorter limbs actually keeps the body warmth closer to the core, which is really the most vital in order to prevent hypothermia. Hypothermia is when your body temperature gets way too low. Then your organs stop working which is which is bad. That's what leads to death so with in order to avoid hyperthermia you need to keep your body warmth close to your core and Having shorter limbs means a less heat radiating surface keeping that warmth toward the core Also, this large barrel chest helps keep heat near the core right this sort of roundedness shape keeps heat towards the core so In many ways the modern human being more length lanky being taller These are kind of the opposite of cold weather adaptations These are more hot weather adaptations when we talk about modern humans and their physiology We'll talk about how that is really the case of a hot weather adaptation The third has to do with these large sinus cavities. I've been referring to in which Having large sinus cavities is really useful for warming cold air while you breathe. If you have ever been in sort of sub-zero temperature or even really sub what sub 30 degrees temperature, it's really cold. And if you step out from a warm house into the cold, you immediately take in a lung full of air and it hurts, right? You can feel like needles in your chest because your lungs sort of seize up, they cramp up because of the cold. But also Every time we take a breath of cold air, we're actually losing body heat through respiration. So as we're breathing, we're losing a lot of body heat. Having large sinuses that sort of warm the air up before it reaches the lungs really prevents loss of body heat. And that's the whole idea, right? Keeping the heat towards the core. Those sinuses sort of work as little heaters and preventing the loss of body heat. But then they do actually double duty. It's not just warming the air, but these large sinus cavities also help to moisturize the air. Because one of the greatest contributors to hypothermia is dehydration. The more dehydrated the body is, the more susceptible it is to hypothermia. And so the sinus cavities, they warm the air, but they also moisturize the air so that when you breathe, you're not losing as much of your um, the, the... the water in your body. You're not losing the liquids in your body because every time we breathe, we're actually losing some of our liquids in our body and we become more dehydrated. So the drier the air is, the more necessary it is to have large sinus cavities. And if you recall, they're living in Europe, not that far from the large glaciers up in northern Europe. So Glaciers are a major contributor to desiccation of the air, of the environment around it. So these are very cold areas, but they're also very dry areas. And so having these large sinuses would have done double duty as far as adapting to that cold weather environment. Now, one interesting thing about having so many specimens of Neanderthals, which literally there are hundreds of Neanderthal specimens, is that they're not just a bunch of tiny little specimens. is that you can actually take a look at things like the variety of traits from the youngest specimens to the oldest, right? When you only have a few specimens, you can't really look at that. We haven't really talked a lot about juveniles, for example. And yet, in our Neanderthal collections, we actually have an amazing assortment of sub-adult specimens or children ranging from newborn to adult. So this is really the first time that any other hominid other than humans can be studied in detail with regard to development patterns. So studies have shown that although Neanderthal newborns Look, remarkably similar to humans as far as their cranial size and their shape, Neanderthal infants by 10 months of age have clear Neanderthal features in their cranial anatomy. So in other words, those brow ridges, the occipital bun, and so forth. While previous hominids seem to have had much more accelerated development patterns, sort of more similar to the great apes, the array of subadult Neanderthal specimens tell us that although Neanderthal children may have grown faster than modern human children in their early years, so in other words, in the first five years of life, Neanderthal children developed more quickly than modern human children. After the first five years of age, their general overall growth rates would have been very similar to ours. So they mature very rapidly until about five years of age, then they slow down. to about the same rate as humans. And so they too would have had delayed sexual maturation, which we've already talked about, has enormous repercussions from a learning standpoint, right? The further delayed sexual maturity is the longer amount of time of juvenile dependency on the parents, and that means more parental investment in terms of learned behavior. So this tells us that learned behavior was... especially important for Neanderthals, just like it is with humans. And what is this learned behavior? We're probably looking at a mix of social behaviors, as well as cultural behaviors like tool making and hunting and so forth, right? So they had to learn a lot just like modern human children do. So basically, we're looking at for the first time in hominid evolution, we're looking at growth patterns that are very similar to our own. Another interesting aspect of having such a large collection of specimens is the ability to look at the Paleopathology of different individuals right if you recall Paleopathology it means the study of ancient diseases Okay, so when we have a large number of specimens we can actually see evidence of certain individuals who might have had diseases or deformities or They might have even had injury because of their lifestyle. So we can start asking these kinds of questions. What happened to them? What diseases were they susceptible? What sort of injuries were they susceptible to? A couple of specimens in particular give us a lot of insight into the life of Neanderthals. For example, if we look at a site called La Chapelle in France, they found what was termed a Neanderthal old man. Okay, Neanderthal old man dating to about 40,000 years ago. It's an adult, an older adult male. Now, old in Neanderthal context is about 40 years of age, which maybe back when I was first studying about Neanderthals in college, that sounded pretty old, but now maybe not so much. Okay, so 40, right, is pretty standard. And, you know, if you look at modern humans, We did not live past the age of 40 or 50 until very recently, until the advent of modern medicine. So even if you look at it, let's say in the Middle Ages, right, people lived until about 35, 40 years of age. So, you know, reaching 40 was pretty old. Okay, so this guy, this poor guy at La Chapelle suffered from numerous pathological conditions. He had a deformation in the pelvis. He had a crushed toe. He had severe arthritis in several of his vertebrae, giving him a very stooped posture. He had a broken rib sustained not long before death, probably contributing to his death. He was missing many teeth. The mandible and maxilla showed a significant amount of bone loss. Okay, so here we go, boys and girls. This is what happens when you do not brush your teeth. Okay, so this is what happens when you have significant bone loss due to periodontal disease. It starts to actually eat away into the bone. So this guy would have lost his teeth and would not have been able to chew at all, really. All of his food would have had to have been processed in order to be able to eat it. All right, so when we come back in the next segment, we'll continue to talk about another old man specimen. Do a little comparison here as far as what it can tell us about Neanderthals. So please follow me to segment 3.

So, If you recall, we're looking at the occipital bone is the bone in the back of the cranium, the top part, if you recall, is the sagittal bone, the sides of the parietals, and then the back is the occipital bone. And in Neanderthals, they actually have a part of the occipital bone that juts out in what's called an occipital bun. I guess this is sort of like an homage to what a woman's hair bun or something like that, right?

But it's this bony bulge in the back of the cranium, and it looks like you kind of just punched out the back of the cranium a little bit here, and it sticks out. And in modern humans, we don't have that. We don't have that occipital bun.

There is, of course, some evidence that modern humans as Homo sapiens, at the same time as Neanderthals about 100,000 years ago, did in fact have occipital buns. The movie that I'm asking you to see... Neanderthals on trial actually goes into more information about what the adaptive significance is of the occipital bun in Neanderthals versus what we see in modern humans, but this this occipital bun really is also sort of the artifact or the remnant of having a larger brain in which you would have expansion in the vertical part of the cranium and then also in the in the back and bottom part of the cranium so we see in In Neanderthals, it's very rounded on the bottom of the cranium. It's very similar to humans, much more so than Homo erectus or Heidelbergensis. If you recall, Homo erectus had very flat back here, had kind of a triangular-shaped cranium, and then very flat.

And of course, if you go further back in time, early Homo or the Australopithecines had even more flat cranium. So with this encephalization, this increase in brain size, we get... this expansion in the lower part of the cranium. Furthermore, we get quite a lot of prognathism going on in Neanderthals. As I mentioned previously, a lot of that has to do with having a large nasal cavity and having large sinuses.

And so overall, you see that the cranium of Neanderthals, it's ovular. It's sort of a football-type shape, longer cranium than you see with modern humans. Modern humans tend to have much more tucked in cranium.

The face is kind of directly below the brain case, sort of a more globular type of shape. So if you do a side by side comparison, you can really see the major differences between Neanderthals and humans cranially. Here's a reconstruction of Homo Neanderthalensis.

I love this one. I don't know why they always seem to give Neanderthals a slightly dumb look to them. I don't really know why. That large brain size certainly suggests that there's something going on there intelligence-wise.

We're not entirely certain exactly how intelligent Neanderthals were. In some respects, at least culturally speaking, they have highly sophisticated tools, just like modern humans, and so that would suggest sort of equal human intelligence, but we don't find things like art with Neanderthals. We don't find them doing a lot of creative things. That seems to be sort of a distinct hallmark of modern human intelligence.

But there's pretty good evidence that Neanderthals were very intelligent. Furthermore, I also have to point out that, of course, this is an artistic reconstruction that we can't know for certain how much body hair Neanderthals would have had. We can't tell the color of the skin.

We can't tell things like the color of the eyes. They probably would have had larger noses because they do have larger nasal cavities. And they probably would have had quite a bit of prognathism because of these larger nasal cavities.

So they would have looked different. They would have looked different than modern humans. But would a modern human really consider them to be not human is really ultimately the question. All right.

So. Looking specifically at these cold weather adaptations that I've been referring to, we've talked about how Neanderthals have have this sort of robust muscular skeletal, yeah, skeletal, in which looking at some very stocky short limbs, now here's the cool part about short limbs, we see in modern human populations that are in very cold weather climates like the Inuit of Alaska and Canada, they tend to have shorter limbs than other human populations. And that has to do with the fact that you actually lose the most amount of body heat through your limbs. They are these extensions that take blood away from the core, and you lose a ton of body heat through your limbs.

Having shorter limbs actually keeps the body warmth closer to the core, which is really the most vital in order to prevent hypothermia. Hypothermia is when your body temperature gets way too low. Then your organs stop working which is which is bad.

That's what leads to death so with in order to avoid hyperthermia you need to keep your body warmth close to your core and Having shorter limbs means a less heat radiating surface keeping that warmth toward the core Also, this large barrel chest helps keep heat near the core right this sort of roundedness shape keeps heat towards the core so In many ways the modern human being more length lanky being taller These are kind of the opposite of cold weather adaptations These are more hot weather adaptations when we talk about modern humans and their physiology We'll talk about how that is really the case of a hot weather adaptation The third has to do with these large sinus cavities. I've been referring to in which Having large sinus cavities is really useful for warming cold air while you breathe. If you have ever been in sort of sub-zero temperature or even really sub what sub 30 degrees temperature, it's really cold. And if you step out from a warm house into the cold, you immediately take in a lung full of air and it hurts, right?

You can feel like needles in your chest because your lungs sort of seize up, they cramp up because of the cold. But also Every time we take a breath of cold air, we're actually losing body heat through respiration. So as we're breathing, we're losing a lot of body heat.

Having large sinuses that sort of warm the air up before it reaches the lungs really prevents loss of body heat. And that's the whole idea, right? Keeping the heat towards the core. Those sinuses sort of work as little heaters and preventing the loss of body heat. But then they do actually double duty.

It's not just warming the air, but these large sinus cavities also help to moisturize the air. Because one of the greatest contributors to hypothermia is dehydration. The more dehydrated the body is, the more susceptible it is to hypothermia.

And so the sinus cavities, they warm the air, but they also moisturize the air so that when you breathe, you're not losing as much of your um, the, the... the water in your body. You're not losing the liquids in your body because every time we breathe, we're actually losing some of our liquids in our body and we become more dehydrated.

So the drier the air is, the more necessary it is to have large sinus cavities. And if you recall, they're living in Europe, not that far from the large glaciers up in northern Europe. So Glaciers are a major contributor to desiccation of the air, of the environment around it. So these are very cold areas, but they're also very dry areas. And so having these large sinuses would have done double duty as far as adapting to that cold weather environment.

Now, one interesting thing about having so many specimens of Neanderthals, which literally there are hundreds of Neanderthal specimens, is that they're not just a bunch of tiny little specimens. is that you can actually take a look at things like the variety of traits from the youngest specimens to the oldest, right? When you only have a few specimens, you can't really look at that. We haven't really talked a lot about juveniles, for example. And yet, in our Neanderthal collections, we actually have an amazing assortment of sub-adult specimens or children ranging from newborn to adult.

So this is really the first time that any other hominid other than humans can be studied in detail with regard to development patterns. So studies have shown that although Neanderthal newborns Look, remarkably similar to humans as far as their cranial size and their shape, Neanderthal infants by 10 months of age have clear Neanderthal features in their cranial anatomy. So in other words, those brow ridges, the occipital bun, and so forth.

While previous hominids seem to have had much more accelerated development patterns, sort of more similar to the great apes, the array of subadult Neanderthal specimens tell us that although Neanderthal children may have grown faster than modern human children in their early years, so in other words, in the first five years of life, Neanderthal children developed more quickly than modern human children. After the first five years of age, their general overall growth rates would have been very similar to ours. So they mature very rapidly until about five years of age, then they slow down. to about the same rate as humans.

And so they too would have had delayed sexual maturation, which we've already talked about, has enormous repercussions from a learning standpoint, right? The further delayed sexual maturity is the longer amount of time of juvenile dependency on the parents, and that means more parental investment in terms of learned behavior. So this tells us that learned behavior was...

especially important for Neanderthals, just like it is with humans. And what is this learned behavior? We're probably looking at a mix of social behaviors, as well as cultural behaviors like tool making and hunting and so forth, right?

So they had to learn a lot just like modern human children do. So basically, we're looking at for the first time in hominid evolution, we're looking at growth patterns that are very similar to our own. Another interesting aspect of having such a large collection of specimens is the ability to look at the Paleopathology of different individuals right if you recall Paleopathology it means the study of ancient diseases Okay, so when we have a large number of specimens we can actually see evidence of certain individuals who might have had diseases or deformities or They might have even had injury because of their lifestyle. So we can start asking these kinds of questions. What happened to them?

What diseases were they susceptible? What sort of injuries were they susceptible to? A couple of specimens in particular give us a lot of insight into the life of Neanderthals. For example, if we look at a site called La Chapelle in France, they found what was termed a Neanderthal old man. Okay, Neanderthal old man dating to about 40,000 years ago.

It's an adult, an older adult male. Now, old in Neanderthal context is about 40 years of age, which maybe back when I was first studying about Neanderthals in college, that sounded pretty old, but now maybe not so much. Okay, so 40, right, is pretty standard.

And, you know, if you look at modern humans, We did not live past the age of 40 or 50 until very recently, until the advent of modern medicine. So even if you look at it, let's say in the Middle Ages, right, people lived until about 35, 40 years of age. So, you know, reaching 40 was pretty old.

Okay, so this guy, this poor guy at La Chapelle suffered from numerous pathological conditions. He had a deformation in the pelvis. He had a crushed toe.

He had severe arthritis in several of his vertebrae, giving him a very stooped posture. He had a broken rib sustained not long before death, probably contributing to his death. He was missing many teeth. The mandible and maxilla showed a significant amount of bone loss.

Okay, so here we go, boys and girls. This is what happens when you do not brush your teeth. Okay, so this is what happens when you have significant bone loss due to periodontal disease.

It starts to actually eat away into the bone. So this guy would have lost his teeth and would not have been able to chew at all, really. All of his food would have had to have been processed in order to be able to eat it.

All right, so when we come back in the next segment, we'll continue to talk about another old man specimen. Do a little comparison here as far as what it can tell us about Neanderthals. So please follow me to segment 3.

Transcript for:Neanderthal Cranial Features and Adaptations

Transcript for:
Neanderthal Cranial Features and Adaptations