Two neighbors in central Michigan recently spent four days digging up bones, 42 of them in total -- the remnants of an ancient mastodon, which experts believe was killed and carved up by humans.

It was just another job for a Daniel LaPoint Jr., a contractor with plenty of digging experience. But when LaPoint came upon a four-foot bone protruding from the dirt while excavating his neighbor's yard, things got a bit more interesting than usual.

"I spend quite a bit of money to go on hunting trips," LaPoint told the Lansing State Journal. "All the sudden this became a hunting trip right in the neighbor's backyard."

The massive rib bone was just one of 42 fossils -- icluding several leg, shoulder and hip bones, as well as the base of one tusk and several vertebrae fragments -- now removed from Eric Witzke's backyard in Bellevue Township. All 42 bones belong to a single mastodon, thought to be somewhere between 10,000 and 14,000 years old.

Experts brought in to assist LaPoint and Witzke estimate the specimen was a 37-year-old male. Tool marks in several of the bones suggest the animal may have been butchered by ancient humans.

Most of the bones will soon find a new home in the University of Michigan's Museum of Paleontology. LaPoint and Witzke will each keep a few bones for themselves to help savor the memory.

"The scientific value is really the new perspective, the new information, that specimens like these can bring," Daniel Fisher, the director of the museum.

There have been 330 mastodon bone discoveries in Michigan in the past year -- including the discovery of a tooth by a nine-year-old boy -- but it is rare that so many bones are found together.