U-M’s mastodon man calls it a career after decades of solving Ice Age mysteries

• Dan Fisher is retiring after 44 years at the University of Michigan, where he became a foremost expert on mastodons
• His research has contributed to the understanding of the Ice Age but also has proven controversial
• Fisher posits that humans may have hunted the massive mammals to extinction and used glacial ponds as refrigerators

ANN ARBOR — Dan Fisher came to the University of Michigan to study fossilized horseshoe crabs.

When he retires at the end of 2023, Fisher will leave U-M as one of the world’s foremost experts in mammoths and mastodons, the elephant-like giants of the Ice Age.

His retirement marks the end of a 44-year tenure at the university, where Fisher stumbled upon his area of expertise while assisting on two mastodon paleontology digs shortly after he arrived at the school in 1979.

“The second one was an animal that showed signs that humans had been associated with that animal,” said Fisher, who curates the U-M Museum of Paleontology. “We couldn’t tell if they had killed the animal, but they had almost certainly butchered the carcass.”

In the ensuing four decades, Fisher became a preeminent scholar of the elephant relatives that once roamed North America, with a particular knack for using their graves to learn more about the continent’s early human inhabitants. 

Fisher’s research has triggered renewed debate about when humans arrived in the Americas, shed light on mastodon mating rituals and early human hunting tactics, and expanded the conversation about what might have caused the animals to go extinct 11,000 years ago.

He’s also known for unconventional research tactics, such as butchering an elephant with primitive tools to show that similar markings on mastodon bones are evidence of human hunting, or sinking a butchered horse in a pond to test the theory that humans used ponds as massive meat refrigerators. 

The horse experiment began when Fisher noticed an intriguing pattern: Most of the mastodon remains he was studying were found at the bottom of what were once ancient ponds. 

“It had something to do with preserving the meat,” he thought.

Native Americans and mastodons existed in the Great Lakes region at the same time around 12,000 years ago, and Fisher said mastodons would have provided meat for food, hides to make clothing and shelter, and huge bones to make tools. 

But the massive animals couldn't be consumed all at once, so Fisher surmised that humans stored butchered mammoths at the bottom of frozen ponds to prevent the meat from spoiling.

An opportunity to test that theory came on a cold February night in the 1990s, when a 1,500-pound draft horse died on fellow paleontologist Catherine Badgley’s farm near Chelsea

“He thought, here's an opportunity,” said Badgley, who helped Fisher butcher the animal and sink it in a winter pond.

Fisher would occasionally exhume portions of the horse, checking (even tasting) the meat for signs of spoilage. For months, Badgely said, it continued to look “like fresh red meat from the supermarket.”

“That's probably the most unusual experiment we did,” she said.

Fisher’s bold research has at times made him a controversial figure. He was among authors of a 2017 study in the journal Nature, which concluded humans butchered a mastodon in present-day California some 130,000 years ago — 110,000 years earlier than previously thought.

Some researchers have challenged that theory.

“Such extraordinary claims require extraordinary evidence, which their paper and supporting materials fail to provide,” several of them wrote in the journal PaleoAmerica.

But admirers of Fisher say his willingness to posit bold theories is what makes him such a valuable scholar. He has often been proven right, said Cory Redman, science curator for the Grand Rapids Public Museum.

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“He knows his stuff,” Redman said. “If he presents an idea, and we’re like ‘Dan, that seems a little bit out there,’ then you think it’s coming from Dan Fisher so maybe we should give it a second thought.”

Having studied more than two dozen sets of mastodon remains found in Michigan, Fisher has learned to read them like a book, with each bone, tooth, and tusk representing a different chapter in the animal’s life story. 

His list of groundbreaking research contributions is long.

He was the first to discover that the growth rings on elephant tusks are embedded with chemical clues into their life history. 

By analyzing the tusks of a mastodon found on an Indiana peat moss farm, Fisher crafted a historical record of the animal’s migration patterns more than 13,000 years ago.

And he was among the first to posit that the animals were hunted by humans — and later that human hunting may have contributed to their extinction.

Just as importantly, colleagues said, he is known as a generous collaborator more than willing to share his deep knowledge. Redman recalled Fisher’s willingness to answer even the most basic questions posed by a crew excavating mastodon bones in Kent County last year.

“Not only is he this amazing scientist, extremely detail oriented, really knowledgeable on all different topics,” said Redman. “He's just a really nice, easy to get along with, down to earth guy.”

Though he may be retiring from U-M, Fisher continues to work on another wave-making theory about the animals’ relationship with humans. 

He believes humans hunted them to extinction some 11,000 years ago, while other scientists have posited climate change was to blame. 

Fisher said he draws his conclusion from a body of evidence collected over decades that suggests humans depended upon access to the long-lived, slow to reproduce animals for survival.

“That reads as evidence that humans are responsible for causing the extinction of these animals,” he said.

As a professor emeritus, he’ll keep studying several mastodon specimens, hoping to test the theory.