Pothole at Harmony Mills where Cohoes Mastodon was discovered

The main concentration of skeletal remains were located 60 feet below the surface

The Cohoes Mastodon's bones before they were assembled and mounted

Standing in the foreground with rock hammer in hand is James Hall, a notable geologist and paleontologist who became the New York State Museum's first director in 1870. Hall assisted with the excavation of the Mastodon's bones and helped acquire the impressive specimen for the collections at the New York State Museum.

Harmony Mills in Cohoes, New York

For the past 150 years, the Cohoes Mastodon has been a beloved feature of the New York State Museum. Learn more about its life and origins, its ancient and modern past, and how the Cohoes Mastodon will continue to intrigue and thrill Museum-goers for years to come.

The Cohoes Mastodon was discovered in 1866 during construction of Harmony Mill No. 3 near Cohoes Falls on the Mohawk River. The Mastodon's remains were found deep within an Ice Age pothole, buried beneath layers and layers of thick soil and muck that had amassed over the course of 13,000 years.


As construction crews were breaking ground for the new mill, they had to clear out several thousand loads of soil and peat, branches, tree trunks, and thick clay to make room for the building's foundation. There, 25 feet below the surface, they uncovered the lower jaw bone of a massive creature. Suspecting more bones might be present, they continued to dig an additional 25-30 feet, unearthing the skull, tusks, leg bones, and ribs of what scientists then knew to be a mastodon.



When alive. the Cohoes Mastodon weighed between 5-6 tons (10,000-12,000 lbs) and measured over 8 feet tall at the shoulders. The size and density of its bones indicate that it was male and we know from carbon dating that he lived about 13,000 years ago.


His life, however, was short-lived and full of hardship. Evidence of trauma points to multiple broken bones, and chemicals present in his bones and teeth reveal he suffered from several bouts of malnutrition. While the average life expectancy for mastodon was was approximately 50 years, the Cohoes Mastodon suffered an early demise at 32 years of age.

8.5 Feet Tall

15 Feet Wide


Over 13,000 years ago near the end of the Pleistocene, the Cohoes Mastodon roamed in upstate New York alongside mammoths, giant beavers and giant ground sloths. As an herbivore, or plant-eater, he would have grown up in a wooded area where he could easily browse on his favorite foods including the twigs and branches of low-lying trees such as spruce and pine.



In his youth, he would have stayed with his mother in a herd that included other mature females and mastodon young of both sexes, waiting for the day when he became a mature male and could explore the world on his own.



At the age of 11, the Cohoes Mastodon was injured in such a musth battle when he received a blow to his lower right jaw from the tusk of another male mastodon (females did not grow tusks).

Male mastodons reached sexual maturity between the ages of 10 and 12 years old, and would become solitary creatures that only gathered together with the herd during breeding season.


Much like modern male elephants, during certain times of the year male mastodons underwent a period called musth, which was characterized by an increase in reproductive hormones and highly aggressive behavior. Fights between competing males were violent and sometimes deadly.





At the age of 11, the Cohoes Mastodon was injured in such a musth battle when he received a blow to his lower right jaw from the tusk of another mastodon.

The blow knocked the forward molar out of alignment and prevented the development of the rear molars, likely making it very difficult for him to chew on the right side of his mouth. While this battle did not kill him, it did result in stunted tusk growth and some nutritional stress.


The life of the Cohoes Mastodon culminated at age 32, when he was again involved in a musth battle, this time with a tragic result.

The competing mastodon landed a tusk jab to the left temporal region that pierced his skull and killed him. We know that he died soon after this battle

because there are no signs of healing on the

damaged area of the skull.


So, while we know that the Cohoes Mastodon had a hard time chewing, it wasn't starvation that killed him. Thirteen thousand years ago, a violent musth battle ended the life of the mastodon that was found in glacial pothole at Harmony Mills in 1866.

Today, the Cohoes Mastodon is cherished as a great treasure for the New York State Museum. More importantly, he provides a unique view into New York's past and valuable context for how the ecosystems of New York State arose.


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