Roughly 50,000 years ago, two species of humans met in the shadow of Eurasian ice sheets. One, Homo sapiens, had just embarked on its conquest of the world after leaving Africa. The other, Homo neanderthalensis,

Neanderthals and humans likely mixed and mingled during a narrow time frame 45,000 years ago, scientists reported Thursday. Researchers analyzed ancient genes to pinpoint the time period, which is slightly more recent than previous estimates for the mating.

Neanderthals interbred with modern humans 47,000 years ago, passing down DNA that still exists in many modern-day people, according to two new studies.