According to Encyclopedia Britannica, Homo neanderthalensis, or better known as the Neanderthals, were a subspecies of humans that went extinct about 40,000 years ago. Little is known about the intricacies of when they came into existence, and how exactly they split off from the lineage to form their own unique group, but the oldest accepted claim of Neanderthals is about 800,000 years ago. The Neanderthals went extinct due to climate change and or disease, but the specifics are unclear.
The first Neanderthal to be found, known as Neanderthal 1, came into human consciousness in 1856. It was found in Neander Valley, presently Germany, by Kleine Grotte. The specimen was found in a cave, which was very fitting seeing their lifestyle. Much of what is known about Neanderthals points to them living lives centered around cave-dwelling life, as cave art and home items have been found in various caves linking back to the Neanderthals.
Due to the first scientific depiction of Neanderthals, society views them as crass and brutish, lacking in sophistication and intelligence, but where society lags behind, science has now made the assertion that Neanderthals actually were far more complex than originally given credit for. They were certainly able to produce fire, make stone tools, clothing, even basic cloth, paints, bows, and may have had an articulate language. They had a fleshed out religion, which oftentimes practiced brutals, hence why we have so many examples of Neanderthals. They were alpha predators of their environment, mainly hunting megafauna, specifically the wooly rhino. It is argued that they are the primary reason for the wooly rhino’s extinction in Europe, which in turn may have led to their own extinction.
The relationship between the Neanderthal and its surrounding megafauna is actually quite pivotal to understanding its extinction. The currently accepted theory on how and why Neanderthals went extinct was due to over hunting. Neanderthals were so successful in their hunting of megafauna, that they had no need nor will to diversify and learn how to hunt smaller organisms, like rabbits or foxes. When they eventually hunted the wooly rhino to extinction, they lacked the technological and cultural developments to hunt other prey. Due to their large size, their bodies' demand for food was much higher than their counterparts, so the temporary lack of resources affected them greater than it would have affected other proto-human species. In this strange relationship, their unparalleled success with hunting megafauna actually may have been the root to their downfall.
Homo neanderthal brain size was larger than the average modern human brain. This is to be expected, since Neanderthals were typically heavier and more muscular than modern humans. They featured a distinctive skull shape that was long and low, with a rounded braincase. The back of the skull had a bulge called the occipital bun and a depression (the Suprainiac fossa) for the attachment of strong neck muscles. Although the brains of our ancestors and Neanderthals were similar in size, Neanderthals had larger brain areas related to vision and body control (Lab, C. 2015).