Pam Groves pinched her nose as she brushed chilly mud from the bones of an extinct bison, a rotten-egg odor billowing from gristle that clung to the animal’s bones. She raised her head to examine the horizon, cautious of bears who could be drawn to the meat of a creature that died 40,000 years ago.
Groves and Dan Mann, both researchers at the University of Alaska Fairbanks, discovered practically the full skeleton of a steppe bison that died during the last ice age in the melting bank of a northern river in July 2012.
Mann and Groves have been canoeing along lonely northern rivers for 15 years hunting for scattered bones of ice era beasts, always hoping to uncover a complete skeleton or mummy of an ice period mammoth, horse, or American lion. They rounded a river bend in mid-June on a known stretch of river that flows northward on Alaska’s North Slope and discovered the skull of a huge bison pinned against a willow plant.
“We were paddling downriver, slogging through a horrible squall of hail and wind, thinking about our camping place about a mile downriver,” Groves described the scene. “We observed the upside-down skull with the lower jaw still attached as the hail was breaking up. The teeth were exceptionally white. They were noticeable.”
Their inflatable canoe landed at the base of the 60-foot hill. Groves noticed other bones that indicated her this wasn’t an average scene even before they put on their rubber boots. Though this ever-changing wall has produced countless bones over the years, they were the scattered remnants of ice-age species separated by meandering river movement and the crumbling and re-formation of permafrost-cemented cliffs. Mann compares their typical discoveries to “Pleistocene in a mixer.”
“It’s quite rare to find bones that are still articulated (together),” he explained. “We’ve never discovered something so complete before. When we locate single lion bones, I think it’s incredibly thrilling.”
Groves and Mann worked for four hours to meticulously remove soil from the cranium. Mann measured the steppe bison’s horn spread to be 43 inches when he lifted it out. The horn tip spread of the record Boone and Crockett contemporary bison is 27 inches. Dale Guthrie, a Pleistocene animal researcher in Fairbanks, estimated that this bison, dubbed “Bison Bob” by Mann and Groves, was a 12-year-old male.
Groves and Mann camped for the night after safely storing the skull in the front of their boat. When they returned to the site, they discovered more bones protruding from the frozen bluff sediments. Ligaments held the bones of each leg together. Some bones were covered in reddish-brown hair.
“I got pretty excited when I noticed the fur,” Mann remarked.
Transporting skull by helicopter
For the following three days, the couple worked the bluff, bringing up buckets of river water to defrost the fragments of their unusual treasure. Except for a left shoulder blade, they found every piece of the animal’s skeleton.
Mann and Groves waited for a helicopter to transport the bison to a safer location as a few hundred bison parts attracted blowflies in their tent.
They used a satellite phone shortly after their discovery to try to contact archaeologist Mike Kunz, their longtime collaborator at the Bureau of Land Management. Kunz is fascinated with the ancient Paleoindians who formerly lived on Alaska’s North Slope and what led them and bison to become extinct some 10,000 years ago. Bad weather kept Kunz confined to the archaeological site he was excavating hundreds of miles away, but a chopper came near Mann and Groves and carried Bison Bob to a BLM camp on the North Slope. Someone put the bones in a predator-proof case there.
Bison Bob was soon on a plane to Fairbanks, where he now lives in a freezer at the same temperature as the cliff where he was entombed. Groves and Mann believe Bison Bob was preserved so well because the bison became entangled in quicksand 40,000 years ago. Bison Bob was buried by the river, and his body became permafrost. Groves and Mann happened to float by just as Bison Bob emerged for the first time from the falling bluff.
“It was a complete coincidence,” Mann remarked. “If we had arrived two days later, he would have been buried by a landslide.”
The steppe bison, which appears in cave art in Spain and France, thrived in Alaska during the ice age alongside mammoths, musk oxen, horses, caribou, lions, wolves, and two species of bears. Bison Bob was a Bison priscus, which evolved into the buffalo we know today, however Bison Bob and his ilk were more than a foot taller and 25% larger.
More intact than Blue Babe
Though researchers and miners have discovered other steppe bison in Alaska, most notably Blue Babe, which is on exhibit at the University of Alaska Museum of the North, Bison Bob stands out for the completeness of the skeleton (a lion had killed Blue Babe, and other animals scavenged the carcass, which was missing its pelvis and parts of its legs).
“This is the type of stuff we’ve always wanted to find,” Groves said. “An full skeleton contains a wealth of information: because he had hair (the remnants), you can tell what colors he was; and with teeth, horn sheaths, and hooves, you can undertake isotope analysis to determine what he was consuming and how his diet may have varied over the course of a year. You might even be able to identify if he spent the winter in the Brooks Range.”
Mann believes that the fleshy sections of Bison Bob will be useful in learning more about him.
“It has wonderful DNA,” Mann added.
Groves stated that once the researchers have completed much of their investigation of Bison Bob, she would like to make castings of his bones and reassemble them for display at the UA Museum of the North.
“Then people will be able to see what a giant bison looked like,” she explained.