Mammoths and mastodons are huge — both in size and in how frequently their remains are found here in Indiana! At the Indiana State Museum and Historic Sites, our collection has one of the largest collections of mammoth and mastodon fossils in the Midwest. Our most iconic is Fred the Mastodon, who greets visitors as they enter Gallery One.
But since the two species look so similar, even celebrity mastodons like Fred are often mistaken for mammoths, and vice versa. We’re here to answer one of the most commonly asked questions at the museum: What’s the difference between a mammoth and a mastodon?
Before we dive into their differences, we should explore why these two animals are so similar in the first place. Mammoths and mastodons both originally evolved from a common African ancestor and belong to the same taxonomic Order as modern-day elephants, Proboscidea. 
But around 25 million years ago, the ancestry split and mastodons became part of the Mammutidae family. Approximately 20 million years later, mammoths diverged from elephants, but remained in the Elephantidae Family. Now that they’ve separated, how can we tell which is which? There are a few key characteristics paleontologists look for.
One of the easiest ways is to look at their tusks. Like their ancestors, mammoths and mastodons both have tusks that grew throughout their lives, but mammoths’ tusks tend to point downward and curl inward, while mastodon tusks are straighter and tend to point outward in front of their face.
Teeth are also important clues for paleontologists. “The forms of mammal teeth are incredibly diverse, reflecting the wide array of functions for which they are used,” said Dr. Catalina Tomé, our curator of paleobiology. “This provides an excellent tool for determining mammal identifications, as with mammoths and mastodons.”
Mammoths were grazers that likely ate tough grasses, so the tops of their teeth were flatter with lots of grooves, allowing them to grind at plants, much like modern elephants’ teeth. Meanwhile, mastodons were browsers that likely ate a crunchier diet of shrubs, trees and leaves. The tops of their teeth had lots of cone-shaped cusps to allow them to chew through the tougher materials on their menu.
Scientists also look at the size of an animal to help determine its species. In short, mammoths are bigger than mastodons. While there are different species of mammoths and mastodons with variations occurring between them, the typical American mastodon stood between 8 to 10 feet tall at the shoulder and weighed between 4 to 6 tons, while mammoths tended to weigh between 6 and 8 tons and stood 10 to 12 feet tall at the shoulder.
There are additional differences that are a little harder to determine at a glance. For instance, mastodons tended to have stockier bones and flatter, broader skulls while mammoths’ heads were more compressed from front to back and had a protruding dome. Both species were extremely common in North America but became extinct close to the end of the last Ice Age around 11,600 years ago.
Today, their fossils have been found in most of the counties in Indiana. During your next visit, check the map in our Frozen Reign gallery to see if a mammoth or mastodon (or both!) has been found in your county!
