I wrote this post originally back in April 2016.
A new study has come out showing that the Y chromosome of Neanderthals was never passed on during the interbreeding that took place between modern humans and Neanderthals. This means hybrid males were either miscarried or infertile. I may be wrong here, but I would think this also means that double the amount of interbreeding took place than was originally thought, just half of the inbreeding didn't result in fertile offspring. So while all non-Africans' DNA is somewhere between 1%-4% Neanderthal, it would be a lot more had the Y chromosome been inheritable.
These findings are particularly interesting, given that virtually all of the information gathered on Neanderthals has hinted that we weren't really a separate species after all, but more likely a subspecies. But if we weren't able to reproduce and create fertile offspring, we must have really been a separate species - though it was close since female hybrids could still be born fertile.
Anywho, since 'tis the season apparently, below is a write-up of a good bit of what I know about Neanderthals. Some things are sourced here, and I'll add more sources as I find where I read the information from.
I'm going to call Homo sapiens Humans because specifying sapiens looks stupid after a while. All members of the Homo genus are considered Humans, though!
Upon the discovery of Neanderthal remains, the scientific community and laymen alike assumed they were a primitive cave men species, possibly an ancestor, who lived in what was the freezing tundra of Pleistocene Europe. As the years have gone by, the scientific view on this has changed drastically.
Morphology
(
Neanderthals, living in the north during the series of ice ages that was the Pleistocene Epoch for most of their existence, were well-adapted to cold climates. Males averaged 165 cm (5'5") tall and 64.9 kg (143 lb) while females averaged 155 cm (5'1" tall and 54 kg (119 lb).
Neanderthal rib cages were more barrel-shaped than modern humans, with the lower ribs flaring out somewhat, similar to other apes'. Their hips were larger as well, contributing to their more bulky frame, which allowed body heat to be more centralized than the slender body shapes of most other species in the Homo genus. It is thought the hips were larger partially in order to accommodate the larger skulls Neanderthals had, a necessity to make birth possible.
Neanderthal faces were in general larger, with a shorter, sloped forehead. The eye sockets were much larger than humans', and it is thought this adaptation was a result of living in lower-light conditions. Their eyes were approximately 6 mm in diameter larger than human eyes. The skull shape was different as well, reflecting the increased importance of eyesight. The Occipital Lobe, the visual processing center of the mammalian brain, was much larger than that of other human species. One of the most striking differences Neanderthal skulls have from Sapiens skulls is the presence of the Occipital bun at the back of the head.
The front teeth of Neanderthals were also larger, and they lacked a prominent chin.
Here is a Neanderthal Skull I made based on images of Neanderthal skulls. It is 204 mm from the center of the eyebrows to the very back of the skull, and 135 mm from the widest part of the skull to the other side (the cheekbones).
Here is my attempt to do forensic facial reconstruction on the skull using human tissue depth measurements. Don't mind the probably way too large ears. I hate modeling ears and so for some reason I make them the largest, most obvious feature. They probably looked nothing like this but I had fun doing it and it doesn't too terribly different from what artists have guessed they would look like.
Hunting and Diet
It is thought for several reasons that Neanderthals hunted with close-quarters weapons.
Neanderthal shoulders were different than Human shoulders in a way that scientists believe would not allow them to throw objects very far. Matched with their stocky, hardy build, it is thought that Neanderthals relied on short-ranged and melee weapons for their hunting. They likely hunted in larger groups, relying on surrounding their prey instead of attacking it from afar. Given that their prey is believed to have more often been mega-fauna than Humans', this hunting strategy seems more effective anyways. Additionally, Neanderthal women are thought to have engaged in hunting as well (by their injury rate, which isn't quite as low as it was for Human women). Females helping out in hunting makes sense as they are thought to have lived in smaller communities and formed larger hunting groups than Humans.
The bones of Neanderthals often have lots of evidence of injury. One researcher noted that the rate and type of injuries are consistent with those of modern day rodeo jockeys, with a large amount of injuries in the head and neck. This could just because those are the least protected areas, especially in bulky Neanderthals, but it may still be worth noting. The large amount of injuries, however, is likely a result of their close-quarter combat with the mega-fauna such as mammoths, rhinos, stag-moose, Auroch, and more that so defined the Pleistocene epoch frozen north.
Studies on the tarter caked onto Neanderthal teeth have found cooked plant matter, but the most direct evidence has been in found in their fecal matter.
Community and Culture
As mentioned earlier, it is thought that Neanderthals lived in relatively small groups, likely only a couple families in one area. They were also rather secluded from other groups, probably due to the fact that glacial Europe wouldn't have had a very large amount of food. There was likely too much competition to live very close to another group.
There is a lot of evidence of older Neanderthals, which suggests that they cared quite well for each other as they aged. Many of the old Neanderthals also had extensive healed injuries, further indicating their level of care. Neanderthals also decorated the graves of their dead with flowers, lending the first known non-human instance of reverence of the dead. This could mean they had some sort of spirituality as well.
One thing that differentiates Neanderthals from Humans is campsite location. Neanderthals tended to live on the sides of hills and in the caves that are usually most accessible on the sides of hills. Humans in the same time and place tended to live at the top of hills. This allowed humans to scan a larger area for prey, which was a big deal since humans lived in such larger groups. Seeing their prey from a distance probably was more advantageous for humans as well due to their reliance on ranged weapons, whereas Neanderthals may have benefited more from their campsites being less visible in order to ambush prey.
Neanderthal art has been somewhat hard to prove since humans lived alongside them for some of the time. There is pretty good evidence for its existence, however.