As big as the day it last roamed northeastern Pennsylvania 10,000 years ago, a nearly complete ice age mastodon has been introduced to public viewing.

The Marshalls Creek Mastodon is the centerpiece of the new Tusks! Ice Age Mammoths and Mastodons.

The State Museum of Pennsylvania is hosting the traveling exhibition through May 2.

The exhibition has two parts, "Tusks!" – a traveling exhibit from the University of Florida Natural History Museum, and the Marshalls Creek Mastodon – which has undergone a $250,000 remounting for the exhibit.

The "Tusks!" exhibit focuses on mammoths and mastodons, two types of elephant-like creatures that are in the grouping of tusked animals called probicidians.

Mammoths and mastodons roamed much of the Earth's northern hemisphere for 3.5 million years, becoming extinct about 10,000 years ago.

No one is certain why they so recently became extinct.

Mammoths and mastodons skeletons have been found in the same general areas.

Although they look somewhat different, what distinguishes their fossils are the difference in their teeth.

"Between mammoths and mastodons, the easiest way to tell them apart is their teeth," said Robert M. Sullivan Ph.D., curator of paleontology and geology at the State Museum of Pennsylvania. "The teeth of a mastodon have cone-shaped cusps. The mammoth has flat plate-like structures."

"The structures indicate they were eating different things," he explained. "The mastodon was eating twigs and leaves where the mammoth was eating grasses. Mammoths are closer to elephants than mastodons, a more primitive offshoot of the elephant family."

The Monroe County mastodon was found in a Marshalls Creek peat bog in 1968 by John Leap.

Leap was using a drag line to harvest peat, a soil additive and a fuel source, when he found a skull caught in the drag line bucket.

"Leap notified the State Museum, which was then the William Penn Memorial Museum," Sullivan said. "The museum sent a crew and they determined it was a mastodon."

They sampled the bog to determine the location of the remaining bones, then constructed a retaining wall and drained that portion of the bog.

They removed a 90 percent complete mastodon skeleton. The body was largely complete with only the trunks and toe bones missing. It was the most complete mastodon skeleton ever uncovered in Pennsylvania.

Unfortunately, the State Museum did not have a large enough space to display the complete mastodon.

As a compromise, they mounted half the mastodon on a wall behind a plexiglass panel. So, it stayed that way for 40 years.

"I thought, wouldn't it be nice to take it out of that panel and assemble the entire skeleton," Sullivan said, "I proposed it to our director and he went for it. We contacted Phil Fralley productions of Hoboken, N.J., a company specializing in mounting skeletons in a state of the art fashion."

Fralley proposed a system where each bone would be wrapped in a steel armature, and suspended in a natural position supported by a cantilevered steel framework.

This was quite a project as the mastodon, which once weighed up to 10,000 pounds, when assembled to standing height is now nine feet high at the shoulder and 14-feet high to the tip of its raised tusks.

The Marshalls Creek Mastodon is believed to have been 25 - 30 years old at the time of its death, based on tooth wear measurements.

Today, elephants in the wild live about 65 years. The specimen is also believed to be a male based on the size of its tusk sockets, which are larger in the male.

"The remounting of the mastodon is being underwritten by a 'Buy A Bone Campaign,'" said Howard Pollman, marketing director of the Pennsylvania Historical & Museum Commission. "We have already raised $45,000 of the $250,000 needed. Each of the tusks raised a sponsorship of $20,000."

The State Museum of Pennsylvania is at 300 North Street in Harrisburg, 717-787-4980. Museum hours are Wednesday through Saturday, 9 a.m. to 5 p.m., and Sunday, 12 p.m. to 5 p.m.

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