The giant mastodon was designated the official state fossil of Michigan in 2002 through the efforts of students at Slauson Middle School in Ann Arbor, Michigan. This magnificent animal disappeared from North America about 10,000 years ago. The human represented in the rendering above stands 6 feet tall - the American Mastodon (Mammut americanum) is 10 feet tall at the top of its shoulder.

One of the most complete mastodon skeletons ever found was discovered near Owosso, Michigan (displayed at the University of Michigan's Museum of Natural History). The longest and most intact trail of mastodon footprints ever uncovered are also in Michigan, near Ann Arbor (about 30 footprints).

What is the difference between a mastodon and a mammoth?

The American mastadon is different from the woolly mammoth (also found in Michigan but in fewer numbers). Mastodons had straighter tusks and both the body and head of the mastodon is longer and squatter than the woolly mammoth (its back doesn't slope like a mammoth's).

Mastodon's were about the size of an Asiatic elephant of today, but it's ears were smaller than a modern elephants. They had thick body hair similar to a mammoth, but mastodon teeth suggest the diet of a browser, not a grazer (unlike modrn elephants and mammoths). The mastodon also lacks the high, peaked knob on the head seen on the woolly mammoth. Mastadons are an older species, originating in Africa 35 million years ago and entering North America about 15 million years ago.

Source:

Michigan Adventure! Discover Our State Symbols: MI.gov
The State Fossil is a Giant: Michigan.gov

Links:

State Fossils & Dinosaurs - 50 States