Scientists on five continents are hunting for geological evidence to pinpoint exactly when humans became a major force shaping life on Earth. But settling on the date could unleash a larger debate.

Ancient seas left an expanse of rolling gypsum dunes known as White Sands in New Mexico, and within this surreal landscape lies evidence that humans have roamed the Americas for at least 20,000 years.

Another theory is that the behavior is instinctual, as wolves have been known to mask their scent while hunting prey by rolling in mud or animal carcasses. Roman had to do a "walk of shame" with ...

Angler spots something strange in the mud at edge of Utah pond and realizes it’s a human skull and bones, police said.