This June 2012 photo released by the Bureau of Land Management shows University of Alaska Fairbanks researcher Daniel Mann as he holds a steppe bison skull from the last ice age that he and fellow UAF researcher Pamela Groves found together with the rest of its well-preserved skeleton near a lake in Northern Alaska.  Although the Arctic's frozen ground preserves bones remains exceptionally well, said Mann, it's rare to find such a complete skeleton. The bison, which the researchers nicknamed "Bison Bob," dated to 40,000 years ago and still had some fur on it. A research paper published Monday, Nov. 2, 2015 says large ice age mammals may have gone extinct in northern Alaska when grassland turned to peat and rising sea levels covered the Bering Land Bridge. (Pamela Groves/Bureau of Land Management via AP)

This June 2012 photo released by the Bureau of Land Management shows University of Alaska Fairbanks researcher Daniel Mann as he holds a steppe bison skull from the last ice age that he and fellow UAF researcher Pamela Groves found together with the rest of its well-preserved skeleton near a lake in Northern Alaska. Although the Arctic's frozen ground preserves bones remains exceptionally well, said Mann, it's rare to find such a complete skeleton. The bison, which the researchers nicknamed "Bison Bob," dated to 40,000 years ago and still had some fur on it. A research paper published Monday, Nov. 2, 2015 says large ice age mammals may have gone extinct in northern Alaska when grassland turned to peat and rising sea levels covered the Bering Land Bridge. (Pamela Groves/Bureau of Land Management via AP)

Rising seas, peat may have done in large ice age animals

  • By Dan Joling
  • Monday, November 2, 2015 10:57pm
  • News

ANCHORAGE — Woolly mammoths and other large ice age mammals thrived in northern Alaska until environmental changes turned grasslands into peat and rising sea levels submerged the Bering Land Bridge, cutting off their access to Asia, according to a research paper published Monday.

Researchers from the University of Alaska Fairbanks and the University of California studied bones of ice age horses, steppe bison, mammoths and other animals to determine why they died out in what’s now Arctic Alaska.

“We wanted to know how these large animals responded to the rapid climatic changes that characterized that period of Earth’s history,” said lead author Daniel Mann, an associate professor in the Alaska university’s Department of Geosciences.

ADVERTISEMENT
0 seconds of 0 secondsVolume 0%
Press shift question mark to access a list of keyboard shortcuts
00:00
00:00
00:00
 

The study focuses on the Pleistocene Epoch, the geological epoch from about 1.6 million years ago to about 10,000 years ago, and the transition to the Holocene Epoch, the years since then.

“The environment was changing a lot faster” during the Pleistocene Epoch, he said. That had to do with the “astronomical drivers” of the ice ages.

“The Earth’s climate during the ice ages was much more unstable,” he said. “It changed every few thousand years. It flipped back and forth.”

The researchers tested a hypothesis by retired University of Alaska Fairbanks paleontologist Dale Guthrie that populations of large animals varied as vegetation responded to climate change.

The frequent environmental changes led to times when the grasses, sedges and rushes preferred by horses and bison were abundant. But, as warming continued, land transitioned to peat, which discouraged grasses.

In previous ice ages, the land bridge between what’s now North America and Asia would have allowed mammals to retreat from Alaska for Asia when grasslands decreased and peat increased.

However, when the Earth’s large ice sheets collapsed at the end of the last ice age, the melt led sea water to rise by up to 100 meters in 10,000 years, Mann said. That cut off a migration route to the west for animals in northern Alaska.

“That’s what we’re thinking probably happened,” Mann said of their extinction. “A combination of peat invading what was formerly a well-drained, grassy landscape.”

Migrating east was not an option, and heavy mammals with large bodies and tiny feet were ill-suited for peat, he said, unlike caribou.

The extinction of mammals weighing more than 100 pounds has been attributed to overhunting, rapid climate change, loss of habitat and the introduction of diseases, according to the study. The researchers found little evidence connecting extinction to hunting by humans.

The study was published Monday in the Proceedings of the National Academy of Sciences.

More in News

Fire crews respond to the Bruce Fire, July 4, 2025, in Soldotna, Alaska. (Alaska Division of Forestry)
Firefighting crews respond to wildfire outside Soldotna

The 8-acre fire and two “spot fires” of less than one acre each are located near Mile 102 and 103 of the Sterling Highway.

Robert Weaver was last seen at the Doroshin Bay public use cabin on June 25, 2025. (Photo provided by the Kenai National Wildlife Refuge)
Kenai wildlife refuge seeking information on missing man

Robert Weaver was last seen near Skilak Lake on June 25.

The Alaska Dive Search Rescue and Recovery Team conducts a training mission in Seward, Alaska in 2024. Photo courtesy of the Alaska Dive Search Rescue and Recovery Team
Anchor Point fundraiser to benefit Alaska rescue and recovery group

Alaska Dive Search Rescue and Recovery Team is an all-volunteer nonprofit organization established in 2016.

Kachemak Bay Family Planning Clinic staff (left to right) Angie Holland, RN; Jane Rohr, Sonja Martin Young, CNM; Robin Holmes, MD; and Cherie Bole, CMA provide an array of reproductive and sexual health services. (Photo provided by KBFPC)
Kachemak Bay Family Planning Clinic releases report on STI trends on the Kenai Peninsula

The report pulls from data gathered from 2024 to early 2025.

Pool manager and swim coach Will Hubler leads a treading water exercise at Kenai Central High School in Kenai, Alaska, on Tuesday, June 17, 2025. (Jake Dye/Peninsula Clarion)
Swimmers, parents call on Kenai to support Kenai Central pool

The KPBSD Board of Education last week said communities will need to step up and take over administration of pools within the next year.

Traffic passes by South Spruce Street in Kenai, Alaska, on Tuesday, June 10, 2025. (Jake Dye/Peninsula Clarion)
Kenai drops effort to rename South Spruce Street

The resolution would have changed the name to make it clear which road led to North Kenai Beach

Gov. Mike Dunleavy compares Alaska to Mississippi data on poverty, per-pupil education spending, and the 2024 National Assessment of Education Progress fourth grade reading scores during a press conference on Jan. 31, 2025. Alaska is highlighted in yellow, while Mississippi is in red. (Jasz Garrett / Juneau Empire)
Dunleavy calls special session for August

Lawmakers on Wednesday said they were surprised by the move.

A makeshift coffin decrying the risks of Medicaid funding cuts is seen on Thursday, June 26, in front of the Blazy Mall in Soldotna. The cuts were included in legislation passed by the U.S. Senate early Tuesday morning. (Photo by Jonas Oyoumick/Peninsula Clarion)
Ahead of Senate vote, Soldotna protesters defend Medicaid funding

Cuts to the program were included in legislation passed by the U.S. Senate early Tuesday morning.

Most Read