A new study claims the reason why Neanderthals hung on so long in Spain was related to the weather. A new climate model seems to indicate the Iberian peninsula turned into a very arid place about 40,000 years ago, and stayed that way for at least 1000 years. The thinking goes this caused modern humans to stop their encroachment into this area, allowing the indigenous Neanderthals to survive longer than their relatives did in other places.