Early Holocene polar bear skeleton from Norway vs. other ancient remains

A press release issued yesterday (23 January 2018) by the University of Stavanger tells the story of decades of work on the most complete ancient polar bear skeleton in the world, found in 1976 in southern Norway, that culminated in an articulated museum display. This specimen was described in my original research paper, Annotated Map of Ancient Polar Bear Remains of the World (Crockford 2012), which shows how many very early Holocene remains have been found outside current polar bear range.

Finn the ice age polar bear skeleton_U Stavanger_photo 2

The Norwegian island of Finnøy is shown below (magenta circle, far left); Stavanger is just southwest of that location in southern Norway:
Finnoy location_Norway Google maps_marked_PolarBearScience

From the University of Stravanger press release (courtesy Phys.org), my bold:

“Imagine you are 12,400 years in the past. Much of Norway is covered with ice and the present-day island of Finnøy exists as only two small islets. The sea is 40 metres above the current level. A polar bear embarks on a long swim through the icy waters and never reaches land. Some 12,400 years later, the skeleton of that same polar bear is discovered under a basement floor in the village of Judaberg on Finnøy.

The skeleton of the Finnøy Polar Bear is the most complete discovery ever made of a polar bear from the Ice Age. Now, the Finnøy Polar Bear is on display in its own room in the exhibitions at the Museum of Archaeology in Stavanger.

The Finnøy Polar Bear was 28 years old, weighed about 600 kilos and lived in Rogaland at the end of the Ice Age. It was probably among the very last of its kind along the Norwegian coast. The wonderfully preserved polar bear skeleton was found under the floor of a basement laundry room on Finnøy in Ryfylke.

Old bones in a box

At that time, Hanne Thomsen was employed as a quaternary geologist at the Museum of Archaeology in Stavanger. Purely by chance, she found herself in possession of a box of big old bones. After a closer look, Thomsen and her colleagues at the Museum of Archaeology realised that they must be the remains of a polar bear—a very old polar bear. It turned out that the bones had been found while laying a sewage pipe for a new house on Finnøy. This was in 1976. The bones were then placed in a box, not to reappear until 6 years later.

Finn the ice age polar bear skeleton_U Stavanger_skull from press release

At that point, the museum contacts the owners of the house, Sverre and Reidun Asheim, who say that there are more bones under the floor. Hanne Thomsen, Asbjørn Simonsen and Per Blystad, who all work at the Museum of Archaeology, together with zoologist Rolf Lie from the Museum of Zoology in Bergen, are given permission to pull up the floor in the couple’s laundry room—and they make a unique discovery. After digging down through 70 cm of sand and silt, they find a nearly complete skeleton of a polar bear from the Ice Age, encased in a 15 cm layer of clay. They find thigh bones and ribs, as well as remnants of the stomach with partially digested seal bones.

Most complete skeleton of an Ice Age polar bear

The skeleton was encased in clay and under excellent preservation conditions. In other words, the clay protected it from exposure to oxygen.

“When we found it, there were only nine other finds of polar bears from the Ice Age in the entire world. And this is still the most complete Ice Age polar bear from so far back in time,” says Hanne Thomsen.

The polar bear sank to the seabed, under about 25 metres of water, and was quickly buried in clay. Subsequently, when Finnøy rose from the sea, the polar bear’s remains would have been situated at the shoreline for a brief time before the beach moved further down to its current level.

It was purely a matter of coincidence that Mr and Mrs Asheim ended up building their house on the exact spot where the polar bear had found its final resting place.

Cause of death unknown

When the polar bear was dug out, museum experts speculated as to what could have been the cause of death. They concluded that it was unlikely that it died of hunger, as both seal and sculpin bones were found together with the skeleton. So, what happened to the Finnøy Polar Bear is still a mystery. The Finnøy Polar Bear was not entirely complete, and for a 1985 exhibition, they replaced the missing parts of the skeleton with bones from a present-day polar bear on loan from the University Museum in Bergen. Today, the missing bones have been replaced with plastic replicas and the other bear is back in Bergen.

Fully assembled, the polar bear skeleton measures about 2.3 metres in length, is 0.6 metres wide and stands more than one metre high.

The Finnøy specimen is number 33 on the map below, previously described by Berglund et al. (1992) and Blystad et al. (1983). Note the skeleton is not truly an “ice-age” find but falls into the Younger Dryas period, an abrupt return to cold conditions during the very early Holocene. See table below map for details (both from Crockford 2012, pdf here).

Here is the pertinent quote from my original “ancient polar bear remains” post:

“As sea ice does not now extend nearly as far south as southern Sweden (see 3 above), all of the 12,500-10,000 year old NE Atlantic polar bear remains indicate that winter sea ice in the North Atlantic expanded much further south during the “Younger Dryas” cold period (13,000-11,500 BP) – and for 1,500 years or so afterward – than it did in the North Pacific. In the North Pacific, sea ice extent appears to have been at or below current limits by at least 13,000 BP (Condron and Winsor 2012).

In summary, even within the past 12,000 years, sea ice conditions have been very different than they are today and this has affected where polar bears have been able to live.

PB fossils map online version Nov 26

PB ancient remains map notes short Nov 26

References

Berglund B.E., Håkansson S. & Lepiksaar J. 1992. Late Weichselian polar bear (Ursus maritimus Phipps) in southern Sweden. Sveriges Geologiska Undersökning, Series Ca. 81, 31–42.

Blystad P., Thomsen H., Simonsen A. & Lie R.W. 1983. Find of a nearly complete Late Weichselian polar bear skeleton, Ursus maritimus Phipps, at Finnøy, southwestern Norway: a preliminary report. Norsk Geologisk Tidskrift 63, 193–197.

Condron, A. and Winsor, P. 2012. Meltwater routing and the Younger Dryas. Proceedings of the National Academy of Science USA 109 (49): 19928-19933.
doi: 10.1073/pnas.1207381109
http://www.pnas.org/content/early/2012/10/31/1207381109.abstract

Crockford, S.J. 2012. Annotated Map of Ancient Polar Bear Remains of the World. Electronic resource available at http://polarbearscience/references
ISBN 978-0-9917966-0-1. pdf here.

via polarbearscience

http://ift.tt/2DxFDCS

January 24, 2018 at 11:59PM

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