During the last ice age, huge numbers of large mammals roamed the temperate zones of North America and Eurasia that lay south of vast continental glaciers. Familiar animals such as Woolly Mammoths, Woolly Rhinoceroses, Reindeer, Musk Oxen, Steppe Bison and the wild ancestors of domesticated horses along with more exotic creatures such as Glyptodon, a car-sized relative of armadillos and Megatherium, an enormous ground-dwelling sloth were abundant. With the ending of the ice age, which began around 21,000 years ago, many of these species experienced dramatic declines or went extinct. Woolly Rhinos, Mammoths, Glyptodon, and Megatherium went completely extinct, while Bison, Reindeer, Musk Oxen and wild Horse went through serious declines and range contractions.
These population declines roughly coincided with another major event in earth’s history, the global expansion of modern humans. Because of this synchronicity, there has long been debate about whether either is the cause. Did humans fuel their global expansion by hunting these animals to extinction, were they victims of a changing climate, or was it some combination of the two?
To answer this question, we need to know two main things. First, did climate change create extremely inhospitable environments for these species? Second, did the decline of these species coincide with contact with humans?