The spread of grasslands and open steppe with increasingly colder climate possibly favoured humans over Neanderthals; modern humans could push into colder areas with bigger game wearing their fitted clothes, which were more effective at insulating than Neanderthal ponchos; and raw material and animal remain sourcing in the southern Caucasus suggest that modern humans were able to use extensive social networks to acquire resources from a greater area in leaner times, whereas Neanderthals likely restricted themselves to more local sources since most of their stone artefacts were drawn from within 5 kilometers .