New research suggests humans lived in South America at the same time as now extinct giant sloths, bolstering evidence that people arrived in the Americas earlier than once thought.
Scientists are studying dogs around the Chernobyl nuclear power plant to see whether anything in their genes helped their families survive the harshest, most degraded environments.
Our Medieval ancestors left us with a biological legacy: Genes that may have helped them survive the Black Death make us more susceptible to certain diseases today.
A hefty set of tusks is usually an advantage for elephants, allowing them to dig for water, strip bark for food and joust with other elephants. But during episodes of intense ivory poaching, those big incisors become a liability.
Male songbirds usually learn their tunes from adult mentors. But when aspiring crooners lack proper role models, they hit all the wrong notes — and have less success attracting mates.