Science Advances<\/a>, examined data from 50 archeological sites excavated throughout the Americas.<\/p>\nAn international team of researchers from the U.S., Canada and Argentina analyzed animal bones at campsites and identified species, grouped by how much food they provided. UAF anthropology professor Ben Potter and archaologist James Chatters, an adjunct professor in McMaster\u2019s School of Earth, Environment and Society, led the study.<\/p>\n
What they discovered addresses one of archeology\u2019s most contested questions: How did humans spread so rapidly across two continents?<\/p>\n
\u201cOne of\u00a0two\u00a0competing ideas is dietary generalization: exploiting a wide variety of resources that would differ based on region,\u201d said Potter. \u201cThe other is megafaunal specialization: focusing on just a few large-bodied prey.\u201d<\/p>\n
The study focused on three of the earliest and most widespread cultural groups in the Americas: Eastern\u00a0Beringians\u00a0in Alaska and the Yukon, Clovis people across North America and Fishtail Projectile Point people in South America. Within those groups, the researchers concluded that 83 per cent to 88 per cent of their food came from massive plant-eaters such as mammoths, elephant-like gomphotheres and giant ground sloths, collectively known as megaherbivores.<\/p>\n
To reach that conclusion, scientists looked at a variety of data. Bones from prey animals at each of the excavation sites showed what people were eating. They then calculated which and how many animals \u2014 large and small \u2014 could be expected to live in the nearby landscape.<\/p>\n
To account for body size, the team multiplied individual animal counts by each species\u2019 estimated edible biomass.\u00a0Even when the researchers artificially inflated small-animal counts in their models as a test, megaherbivores still accounted for the overwhelming majority of available food.<\/p>\n
\u201cThe test of dietary specialization isn\u2019t just how many of a given animal you find at an ancient campsite,\u201d Potter said. \u201cIt\u2019s\u00a0what the record looks like\u00a0relative\u00a0to natural abundance. If early people were dietary generalists,\u00a0you\u2019d\u00a0expect to find the most common animals would be more common in peoples\u2019 campsites.\u201d<\/p>\n
Instead, they found the opposite.<\/p>\n
\u201cAnimals like mammoths and ground sloths, which were actually quite rare in the landscape, completely dominate the archeological record,\u201d he said. \u201cRabbits and mice, which would have been everywhere, barely register.\u201d<\/p>\n
The focus on large herbivores for food also explains why the early toolkits appear\u00a0very similar\u00a0from California to Maine to Florida, and at sites in South America, Potter said.<\/p>\n
People hunting the same kind of animal across radically different landscapes had no need to adapt their technology to local conditions. The tools found at the archaeological sites included implements for hunting large game, such as large fluted projectile points and specialized butchering implements. Fishing gear and plant-processing tools were notably absent.<\/p>\n
This focus on hunting large prey also explains the rapid expansion of humans from Alaska through South America, the study finds.<\/p>\n
When hunter-gatherers move into unfamiliar territory, they typically need generations to learn the new landscape, how to effectively hunt local small and medium-sized game, and which local plants are edible.<\/p>\n
Building a diet around large mammals changes that dynamic.<\/p>\n
\u201cMammoths, for example, can cover a tremendous range and occupy vast territories,\u201d said study co-author Mat Wooller, a professor at UAF. \u201cIn effect, specialist hunter-gatherers used their knowledge of megaherbivores, like mammoths, to expand successfully across the continents rather than learning about each localized ecosystem they encountered.\u201d<\/p>\n
The study also found that the timing of megafauna extinctions\u00a0tracks with\u00a0human arrival, not all at once, but like a wave moving southward down the continents.<\/p>\n
In Alaska, mammoths and horses disappeared around 13,300 years ago, at the end of the earliest known human occupation there. Clovis-era megafauna in North America\u00a0were\u00a0gone by 12,800 years ago, and gomphotheres and giant ground sloths survived in South America until about 11,600 years ago.<\/p>\n
The same sequence of arrival, overlap and extinction played out again and again, each time a little further south, Potter said. This made a strong circumstantial case for human hunting as a major contributing factor to megafauna extinction, compounded by climate change, which could have reduced their habitat, making them more susceptible to hunting pressure.<\/p>\n
\u201cMegaherbivores reproduce\u00a0slowly,\u00a0space births widely and, as adults, have no natural predators,\u201d he said. \u201cThey would have had no learned wariness of new, technologically sophisticated human hunter-gatherer populations.\u201d<\/p>\n
Members of the research team include Potter, Chatters and Wooller; Luciano Prates of Universidad Nacional de la Plata, Argentina; S. Ivan Perez of Museo Hist\u00f3rico y\u00a0Arqueol\u00f3gico, CONICET, Argentina; Todd Surovell and Robert Kelly of the University of Wyoming; and Gustavo Politis of Universidad Nacional del Centro de la Provincia de Buenos Aires, Argentina.<\/p>\n","protected":false},"excerpt":{"rendered":"New research led by archeologists at the University of Alaska Fairbanks (UAF) and McMaster University reveals that the…\n","protected":false},"author":2,"featured_media":778386,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[49,48,66],"class_list":["post-778385","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-ca","tag-canada","tag-science"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/778385","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/comments?post=778385"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/posts\/778385\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media\/778386"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/media?parent=778385"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/categories?post=778385"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ca\/wp-json\/wp\/v2\/tags?post=778385"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}