WOI/ABC News

An excavation is underway thanks to the discovery of the bones of a prehistoric mammoth in one Oskaloosa, Iowa, family's backyard.

According to ABC's affiliate ABC5-WOI  in Des Moines, the first bones were discovered in July 2010 by a man named John and his two teenage sons when they were walking in the woods of their property looking for blackberries.

One of his sons pointed out what he thought was a ball in the creek below to his family. Once they got closer, John, who has an interest in archeology, noticed a marrow line at the top of the object, said reporter ABC5-WOI reporter Katie Eastman, who interviewed the family.

Realizing this was no ball, the family dug out what has now been identified as a mammoth femur.

Despite discovering the bones nearly two years ago, the bones were brought to the University of Iowa for identification only last month, sparking the interest of Holmes Semken, professor emeritus of Geoscience.

Semken enlisted the help of volunteers from the University of Iowa as well as Iowa State University, to help to uncover the fossils lying six feet below the surface.

The University of Iowa Museum of Natural History is overseeing the project's excavation and research.

"The size of this discovery is quite uncommon," said Sarah Horgen, education coordinator at the museum. "It's pretty exciting-partially because the mammoth is being discovered where it died. And we know that because we're finding very large bones right alongside very small bones."

Horgen says the mammoth is at least 12,000 years old, and was extinct by the end of the last ice age.

Horgen also noted that the mammoth's discovery is not uncommon in Iowa, and that the museum has a working record of reported fossil discoveries around the state.

"The bones discovered could be 100,000 years old or more," she said.

Two digs have been held so far. In addition to the bones found by the landowner, volunteers have since uncovered the mammoth's feet bones, as well as its floating and thoracic ribs.

"The femur is about 4 feet long. The ribs of the diaphragm that move when you breathe are 2 and half feet each. The ribs that connect to the breast bone are 4 feet. You could use one for a walking cane," Semken said.

But what will happen to the mammoth's bones once they've been all dug up?

"The bones really belong to the land owner," said Semken. "Our agreement with him is we get the science."

Semken is interested in finding how the animal died, but more importantly, how it lived.

He plans on studying the pollen samples and seeds lodged within the bones, as well as the compound make up to understand the environment the mammoth lived in, what it fed on, where it fed in terms of grassland as opposed to forest.

Semken says the digs should progress through the summer. He plans to enlist the help of volunteers from William Penn College in Oskaloosa, the local county conservation board, as well as rock clubs around the state to partake in the digs.

"We'll go as long as it takes," said Semken, "We don't know how widely scattered the bones are."

"For us to work with somebody who's so interested in these types of materials and has a working knowledge of what to look for has been really great," Horgen added.  "The landowner is clearly quite interested in the time period."

The landowner could not be reached for comment.