*SO ANCIENT A HORSE -UNEARTHED*

LANDSCAPING IN UTAH uncovers a skeleton that's 16,000 years old.

The horse had arthritis when it died. It is possible, too, that it had bone cancer in one ankle.

That can happen to any horse once it gets to be a certain age. This one is nearly 16,000 years old.

Paleontologists last week identified the skeleton of a horse from the ice age in Lehi, Utah — a particularly unusual discovery given that much of the western part of the state was underwater until about 14,000 years ago. Buried for thousands of years beneath seven feet of sandy clay, the remains were discovered only when the Hill family began moving dirt around their backyard to build a retaining wall and plant some grass.

Laura Hill said she and her husband, Bridger, uncovered the skeleton last September, but didn’t think much of it at first. They wondered if it was a cow; Lehi is about 15 miles from Provo and was once mostly farmland that hugged the edges of nearby Utah Lake. She consulted a neighbor, a geology professor at Brigham Young University, who examined the bones, and guessed they were from a horse from the Pleistocene Era.

“I was shocked,” Ms. Hill said. “This is something we did not expect.”

Utah is home to several fossil sites where dinosaurs and other ice age animals, including mammoths, mastodons and saber-toothed tigers, have been discovered. Horses have roamed North America for 50 million years, said Ross MacPhee, a curator in the department of mammalogy at the American Museum of Natural History. During the Pleistocene Era, the continent was dominated by two kinds of horses, he said, adding that he believes today’s domesticated horses are linked to one of those breeds. Despite harsh conditions, Mr. MacPhee said, “those horses could live anywhere.”