People of Asian and European descent — almost anyone with origins outside of Africa — have inherited a sliver of DNA from some unusual ancestors: the Neanderthals.

These genes are the result of repeated interbreeding long ago between Neanderthals and modern humans. But why are those genes still there 40,000 years after Neanderthals became extinct?

As it turns out, some of them may protect humans against infections. In a study published on Thursday, scientists reported new evidence that modern humans encountered new viruses — including some related to influenza, herpes and H.I.V. — as they expanded out of Africa roughly 70,000 years ago.

Continue reading “Deep in Human DNA, a Gift From the Neanderthals” →

For a hungry fish in search of a meal, a jellyfish would seem to be a huge disappointment. These gelatinous animals are 95 percent water. As a result, a cup of live jellyfish provides just five calories — one-third the amount in a cup of celery.

It should come as no surprise, then, that marine biologists long ago dismissed jellyfish as an insignificant item on the ocean menu. Other animals rarely bothered eating them, the idea went, and so they represented a dead end in the ocean’s food web.

Continue reading “Who Wants to Eat a Gooey Jellyfish? Pretty Much Everyone in the Ocean.” →

How generous is an ape? It’s a hard question for scientists to tackle, but the answer could tell us a lot about ourselves.

People in every culture can be generous, whether they’re lending a cellphone to an office mate or sharing an antelope haunch with a hungry family.

While it’s easy to dwell on our capacity for war and violence, scientists see our generosity as a remarkable feature of our species. “One of the things that stands out about humans is how helpful we are,” said Christopher Krupenye, a primate behavior researcher at the University of St. Andrews in Scotland.

Continue reading “Seeking Human Generosity’s Origins in an Ape’s Gift to Another Ape” →