(CN) – Today most hyenas are pictured hunting and scavenging in Asian and African ecosystems, but a recent discovery of fossil teeth tells a much different story about their pre-ice age range.
The study published Tuesday in the journal Open Quaternary reveals that two ice age fossil teeth discovered in Yukon Territory in Canada belonged to the so-called "running hyena" Chasmaporthetes. Paleontologists, who recovered the teeth in the 1970s, tentatively thought them to belong to hyenas, but the new paper is the first to confirm the fossils' identity and report on them in detail.
The newly described fossils are important in part because they provide the first proof of ancient hyenas living in Beringia and fill an important knowledge gap on how hyenas reached North America. Chasmaporthetes fossils had been found as far north as Mongolia in Asia and the southern United States in North America, with no sites in between.
"Fossils of this genus of hyenas had been found in Africa, Europe and Asia, and also in the southern United States. But where and how did these animals get to North America? The teeth we studied, even though they were just two teeth, start to answer those questions," according to first author Dr. Jack Tsen,g an assistant professor of pathology and anatomical sciences at the Jacobs School of Medicine and Biomedical Sciences at University of Buffalo.
The 1970s paleontological expeditions took place in the remote Old Crow River region in northern Yukon Territory, where Richard "Dick" Harington, Gerry Fitzgerald and Charlie Thomas discovered one tooth and Brenda Beebe and William Irving found the other. The specimens were then tucked away in the collections of the Canadian Museum of Nature near Ottawa, Ontario, along with 50,000 other fossils recovered in the last century from that same area.
The teeth captured Tseng’s attention when he re-discovered decades-old notes by study co-author Lars Werdelin, a paleontologist in the Swedish Museum of Natural History. Tseng drove to Ottawa from Buffalo in February 2019 to view the specimens where he was able to identify the teeth as belonging to the genus Chasmaporthetes.
Tseng estimates the age of the teeth to be between about 1.4 million and 850,000 years old, with ages more likely closer to the older figure. However, because the earliest known hyena fossils on the continent date back about 5 million years, Tseng believes it’s likely the first hyenas crossed into North America long before the animals to which the teeth belong.
"Our previous understanding of where these far-ranging hyenas lived was based on fossil records in southern North America on one hand, and Asia, Europe and Africa on the other," Tseng said. "These rare records of hyenas in the Arctic fill in a massive gap in a location where we expected evidence of their crossing between continents, but had no proof until now."
Study authors believe that ancient hyenas likely entered North America via the Beringia land bridge, an area including Alaska and the Canadian Yukon Territory, that connected Asia with North America during periods of low sea levels. From there the animals likely made their way south all the way to Mexico.
“It is amazing to imagine hyenas thriving in the harsh conditions above the Arctic Circle during the ice age," study co-author and Yukon province paleontologist Dr. Grant Zazula said. "Chasmaporthetes probably hunted herds of ice age caribou and horses or scavenged carcasses of mammoths on the vast steppe-tundra that stretched from Siberia to Yukon Territory."
Though there are only four living species of hyena today – three bone-crushing species and the ant-eating aardwolf. Ancient hyenas, though, had a more diverse family history including many dozens of species found across the Northern Hemisphere. Hyenas disappeared from North America before the first people arrived and the reasons for their extinction between 1 million and 500,000 years ago remain unknown.
Subscribe to Closing Arguments
Sign up for new weekly newsletter Closing Arguments to get the latest about ongoing trials, major litigation and hot cases and rulings in courthouses around the U.S. and the world.
