Death by (lack of) fashion

Neanderthals' failure to make parkas may have sealed their demise: A quartet of researchers at Simon Fraser University in Canada has found evidence that suggests that the reason early humans were able to survive the ice age while the Neanderthal perished is because humans figured out how to make parka-like clothing to keep warm and Neanderthals did not....

The researchers also note that other evidence of humans crafting warm
clothes has been found as well, such as bone needles for sewing and
other tools that could be used to scrape pelts. Also, a set of figurines
wearing parka-like coats and dating back approximately 24,000 years was
found in Siberia. No such evidence of Neanderthals wearing crafted clothes has ever been found.


As to why the Neanderthals would not have crafted clothes to survive
the cold, the researchers suggest they may have lacked the intelligence
or simply because their cultural traditions were standing in the way.

 I can imagine some Neanderthal bloke pointing at some newly kitted out non-Neanderthal guy and saying "ha!  look at the girly man in his new 'parka.'  Clothes are for wusses."