Enlarge (credit: Italian Culture Ministry)

Archaeologists in Italy recently unearthed the remains of at least nine Neanderthals in Guattari Cave, near the Tyrrhenian Sea about 100 km southeast of Rome. While excavating a previously unexplored section of the cave, archaeologists from the Archaeological Superintendency of Latina and the University of Tor Vergata recently unearthed broken skulls, jawbones, teeth, and pieces of several other bones, which they say represent at least nine Neanderthals. That brings the cave’s total to at least 10; anthropologist Alberto Carlo Blanc found a Neanderthal skull in another chamber in 1939.

Italy was a very different place 60,000 years ago. Hyenas, along with other Pleistocene carnivores, stalked rhinoceroses, wild horses (an extinct wild bovine called aurochs), and people.

“Neanderthals were prey for these animals. Hyenas hunted them, especially the most vulnerable, like sick or elderly individuals,” Tor Vergata University archaeologist Mario Rolfo told The Guardian. The archaeologists found the Neanderthal remains mingled with the bones of rhinos, giant deer, wild horses, and other hyenas. Predators and scavengers tend to leave behind different parts of the skeleton than, say, flowing water or simple burial—and tooth marks are usually a dead giveaway.

Comparison of Modern Human and Neanderthal skulls from the Cleveland Museum of Natural History. (credit: hairymuseummatt )

We know that Neanderthals left their mark behind in the DNA of many modern humans, but that exchange worked both ways. The groups of Neanderthals our species met in Eurasia around 45,000 years ago already carried some Homo sapiens genes as souvenirs of much earlier encounters. A recent study suggests that those early encounters allowed the Homo sapiens version of the Y chromosome to completely replace the original Neanderthal one sometime between 370,000 and 100,000 years ago.

Evolutionary geneticists Martin Petr, Janet Kelso, and their colleagues used a new method to sequence Y-chromosome DNA from two Denisovans and three Neanderthals from sites in France, Russia, and Spain (all three lived 38,000 to 53,000 years ago). The oldest Neanderthal genomes in Eurasia have Y chromosomes that look much more like those of Denisovans. Later Neanderthals, however, have Y chromosomes that look more like those of us humans.

Gene flow is a two-way street

Tens of thousands of years ago, our species shared the world with at least two other hominins. The tools, beads, and art they left behind hint that these other humans were probably a lot like us. And we were definitely all alike enough to have, apparently, a bit of sex.