Tag: mammals

A nose for winter

 

3D model of a polar bear skull. Noeska Smit/Gerrit Rijken.

It has been a frosty few weeks here in Bergen with lots of snow and temperatures dipping well below zero. With those bone chilling temperatures it becomes clear very quickly how we humans are poorly designed for such weather. Just breathing in the cold, dry air is enough to start coughing. If only we had a polar bear’s nose!

Polars bear are very well adapted to cold weather. Not only do they have thick fur and a generous layer of subcutaneous fat to keep the chill out, their noses contains a well-hidden structure that warms up and hydrates the Arctic air that they breathe.

The video above shows a 3D model of a polar bear skull collected at Spitsbergen that was scanned by Associate Professor Noeska Smit at the Department of Medical Visualization. Thin and curly structures are visible inside the nose. These are the turbinate bones, fragile bony plates that are covered in a mucosal membrane. The turbinates warm the incoming air and add moisture to it, ensuring that the air that reaches the lungs isn’t too dry. The turbinates’ convoluted structure increases the inner surface area of the polar bear’s elongated nose and helps it withstand the Arctic chill. Pretty cool!

Echoes from the past

Walrus skull with cut off rostrum
One of the many walrus skulls from Svalbard in the collections of the Bergen University Museum. Parts of the rostrum have been cut away (dotted line) to remove the tusks.

 

The walrus’s most distinctive feature is its tusks. They can grow to up to an impressive meter in length, and both males and females have tusks. Walruses were once very abundant in the Svalbard Archipelago, but were nearly hunted to extinction during the Middle Ages for their ivory. Walrus ivory was very popular during the early Middle Ages, and a famous example of objects made out of walrus ivory are the Lewis Chessmen. The growing trade in walrus products in medieval Europe led to overexploitation of walrus populations, and the population on Svalbard was brought to the brink of extinction. In 1952, walruses on Svalbard became protected. The population is slowly increasing but walruses remain on the Norwegian Red List. 

The Osteological collection of the Bergen University Museum contains many archaeological walrus skulls, such as the one in the picture above, that still bear the signs of this overexploitation. According to archaeologist James Barrett, walruses were slaughtered in a consistent way where the frontal part of the skull, the rostrum, was chopped off in order to remove the tusks. The marks left behind by the chopping can still be seen in many of the skulls (indicated by the dotted line).

More on how the North Atlantic walrus ivory trade was linked to the boom and bust of the Norse settlements in Greenland: https://titan.uio.no/naturvitenskap-livsvitenskap-english/2020/boom-and-bust-economy-greenland-norse-walrus-ivory-trade

Season’s greetings from Bergen Osteology!

 

Smalahove is a traditional Norwegian dish made from a sheep’s head and often eaten in the period leading up to Christmas. The name of the dish comes from the combination of the Norwegian words hove (meaning head) and smale (meaning sheep). The dish is considered a delicacy in the western part of Norway, although it is certainly not everyone’s favorite. The head is salted, sometimes smoked, and dried, and is boiled or steamed for several hours before serving. It is served with boiled potatoes and kolrabi mash, and if you need some help washing it down, a little glass of akvavit.

In addition to the cultural delight some of us take in eating this dish every year, it also provides great specimens for our osteological collection. The fact that smalahove is often sold already cut in half means that it gives us a nice sagittal cross section of the sheep skull. This is helpful in understanding the internal anatomy of the sheep’s head, and helps in identifying small skull fragments from archaeological excavations. Can you spot the petrosal bone, the densest bone in the body?

Svalbard reindeer

Reindeer metacarpi from mainland Norway (left) and Svalbard (right), both from our collection.

Svalbard reindeer (Rangifer tarandus platyrhynchus) are a separate subspecies of reindeer, endemic to the Svalbard archipelago. They have relatively small heads, a compact body, and shorter legs than the reindeer found on mainland Norway (Rangifer tarandus tarandus). The latter is clearly illustrated by the photograph above: the bone on the right is a metacarpus of a Svalbard reindeer, the metacarpus on the left is from a reindeer from mainland Norway. The osteological collection of the University Museum of Bergen contains numerous skeletons of both species.