Ecologists use species distribution models to predict how far animals are likely to roam based on sightings. Now, scientists apply a similar principle to ancient humans.<\/p>\n
The new study, led by Ariane Burke, PhD student at Universit\u00e9 de Montr\u00e9al and head of the Quebec-based Hominin Dispersals Research Group, investigated Europe during the last ice age<\/a>, roughly 60,000 to 35,000 years ago.<\/p>\n Throughout this period, the climate fluctuated between colder (stadial) and warmer (interstadial) phases. This was also the time when the first Homo sapiens appeared in the archaeological record, and the last Neanderthals vanished.<\/p>\n The reasons for Neanderthal extinction<\/a> and for modern humans\u2019 survival in Europe are still not entirely understood. The reasons are complex and involve many factors. But a new research, modeled on methods taken from digital ecology, is providing new leads.<\/p>\n How the\u00a0Neanderthals\u00a0got their big noses?<\/a><\/p>\n Instead of using living animals, they used archaeological sites as presence points to map the locations where Neanderthals and Homo sapiens once lived.<\/p>\n The analysis suggested that climate stress<\/a> and competition, the most common explanations for Neanderthal extinction, only account for part of their disappearance. It was a combination of climate change, geography, animal evolution, and interspecies competition, and how each factor weighed in depended on where they were.<\/p>\n Several modeling steps were used in the study. The team constructed four habitat models for both species following a conservation biology and mapping sciences approach. To do so, these models utilized archaeological data alongside other information about changes in geography and climate.<\/p>\n They then contrasted the results and built new models that focused on \u201ccore\u201d regions that were large and resource-rich enough to maintain stable populations, but most importantly, continuous.<\/p>\n Neanderthal\u00a0ancestors may have been early risers<\/a><\/p>\n Ariane Burke, a professor in the Department of Anthropology at Universit\u00e9 de Montr\u00e9al, said, \u201cObviously, we don\u2019t have precise demographic data for populations living 35,000 years ago, so we used ethnographic data from better-documented ancient hunter-gatherer groups to set parameters for the geomatics tools and generate these models.\u201d<\/p>\n \u201cFor example, these data show that the typical annual territory of a local group of 25 to 50 individuals, moving seasonally and maintaining regional connections with other groups, would be about 2,500 km\u00b2.\u201d<\/p>\n Differences between the Neanderthals and Homo sapiens at this point in the study were apparent, even for Neanderthals, though their regions were not as peripatetic as those of Homo sapiens. These groups are connected, which Burke says is crucial because, when there are climate, ecological, or population stresses, we can shuffle about within that network.<\/p>\n \u201cThese networks act like a safety net,\u201d Burke says. \u201cThey allow sharing of information about resources and migrations, forming partnerships, and temporary access to other territories in times of crisis.\u201d<\/p>\n Ancient fat factories? How\u00a0Neanderthals\u00a0processed survival<\/a><\/p>\n Archaeological evidence of material exchange indicates that Neanderthals also possessed networks. However, relative to the models, they had weaker regional connections than their counterparts across Central and Eastern Europe.<\/p>\n The study shows that rapid, unpredictable shifts in climate affected populations far more than changes in temperature or rainfall.<\/p>\n Climate explains only so much of Neanderthal extinction; Ice ages had come and gone (Neanderthals survived earlier ones). Burke says the disappearance stemmed from a combination of factors, some pointing to an unstable climate; others to population pressures and social organization; and that the specific reasons may have been different in each region.<\/p>\n The study, for instance, found that Neanderthals in Europe were divided into western and eastern groups. Weak connections between populations in Eastern Europe may have kept these humble creatures cut off from their brethren as conditions fell. Conversely, in the absence of such groups and given more robust links among core regions across the Iberian Peninsula itself, more groups may have persisted longer.<\/p>\n Ancient DNA reveals the first\u00a0Neanderthal\u00a0family<\/a><\/p>\n However, the story is probably a little more complex than a single explanation.<\/p>\n Homo sapiens may also have brought additional pressures with their movements, which could have proved fatal for Neanderthals in the west, who were already demographically weak. Their interactions were probably complicated (these two species could also interbreed, as we know they did on occasion) and involved competition between lines, hybridization, and other subtle population-level dynamics.<\/p>\n The ancient patterns Burke observed remind us of challenges humans still meet today.<\/p>\n \u201cHuman migration has always existed, supported by mobility and social networks,\u201d she explains<\/a>. \u201cEven now, despite borders, crowded populations, and inequality, people move for the same reasons: to find better places, reunite with loved ones, and join support networks.\u201d<\/p>\n It is a timely reminder that, 40,000 years ago and today, it takes more than tech-smart, clever minds for us to survive. We need connections, relationships, and community building.<\/p>\n Journal Reference:<\/strong><\/p>\n