SALT LAKE CITY (AP) – A vast collection of broken dinosaur bones unearthed in southeast Utah indicates they were smashed underfoot by other dinosaurs shortly after they died, according to paleontologists.

Brigham Young University scientists have spent years analyzing more than 4,000 bones from a quarry just west of Arches National Park.

They say the bone collection — which includes at least 67 dinosaurs representing eight species — suggests a mass-die-off, likely from drought.

After the die-offs, other plant-eating dinosaurs stomped among the carcasses as they passed through, snapping most of the bones at the site, according to BYU professor Brooks Britt, lead author of a recently published study of the bones.

Many bones would have been crushed easily under dinosaurs weighing 20 tons or more with feet larger than tires, Britt said. More than 95 percent of bones studied at the site were broken.

"Some of them were just pulverized," Britt said.

Utah holds some of the country's most well-preserved and numerous dinosaur quarries and is a hotbed for researchers looking for clues to ancient life. The site analyzed by Britt and his team offers insights into the lesser-known lives of dinosaurs and other life forms some 124 million years ago.

It's also a fresh reminder that digging up dinosaur bones isn't as easy as it's often depicted.