Most people associate mummies with the embalmed pharaohs of ancient Egypt. Not all mummies come wrapped in linen though and most are actually created through purely natural means, called natural or spontaneous mummification. Such mummies formes when a dead body lies in an environment that largely slows down its microbiological decomposition. This sometimes happens in very dry, oxygen poor or cold environments, for example within glaciers and ice patches.

Frozen human and animal mummies have melted out of the ice all over the world. Even in tropical areas, like central Africa and South-East Asia, a range of mummified birds and mammals have been recorded at high altitudes. One of the most famous is that of a leopard carcass found on a glacier at the summit of Mt. Kilimanjaro in 1926, which is supposed to have inspired Hemingway’s “The snows of Kilimanjaro”. Another leopard mummy was likewise found in glacier ice on Mt. Kenya in 1997 and was radiocarbon dated to have died about 900 years ago. Most finds of animal ice mummies have, however, been made in the northern parts of the world where a larger number of potential sites have been systematically searched, like Scandinavia and North America. In warm years, with lots of glacial melting, certain ice patches and glaciers are even littered with numerous small bird and rodent mummies.

How did all of these animals get up on the ice to get mummified? Some of the mummies that we find are of animals that naturally visit such places. Others could have been deposited by predators as a food cache for later. However, a large number of them are not of species that we would normally expect to find on high alpine ice, like many of the rodents and tropical species like the leopard. In Grasshopper Glacier in Montana swarms of grasshopper mummies have even been found entombed in the ice. Some of these finds are likely from animals that died while migrating across mountains or after being carried up by strong updrafts. Others are more cryptic and could be an indication of unknown behaviors that should be studied in more detail.

These animal ice mummies are usually extraordinary well preserved, even for ice patch finds, and in line with the famous permafrost finds of mummified Ice Age mammals. The alpine ice mummies vary greatly in age from less than hundred to several thousands of years old. While not as old as the Ice Age permafrost finds, they are usually much more frequent within local areas. They thus provide unique information about natural history that one rarely can find in other sites, and could potentially shed light on the evolution of certain pathogens and parasites.

Polar bears (Ursus maritimus) are usually the bear that one connects with ice, but bones of brown bears (Ursus arctos) have melted out of several alpine ice patches. The ¹⁴C dating of one find from Norway forces us to rethink how we study finds from such sites.

During the unusually warm summer of 2014, the alpine ice in Norway melted a lot and some of the old ice patches were almost gone. These seemingly “ancient” ice patches are often highly visible from nearby villages, and their melting away is a concern for many people. This is also true for the ice patch at Resfjellet in Meldal, which was almost lost that year. During the autumn, a concerned local went up to the small ice patch to investigate the small remains of the ice and discovered that two reindeer skulls with antlers and a bear mandible had melted out of the ice.

The small size of the ice patch and its low altitude made us think that these finds were likely to be quite recent and that the ice patch was relatively young. The radiocarbon results were, however, exciting! As expected, the two reindeer bulls were not that old. One of them had died sometime in the 1950-ies, the other one between 2005-2008, and DNA-samples showed that they had been domestic reindeer. The bear, however, was much older and had wandered around Meldal during the early Viking Age! This find forces us to think larger concerning both the natural and cultural history that is melting out of the ice, as many more sites than what we previously believed might potentially contain old finds and should be investigated.

We don’t know what the bear was doing up on the ice patch during the Viking Age, but more bones might melt out in the future. There are so few bears remaining in Norway today, that we know very little of its high alpine behavior. In North America, grizzly bears have been observed to use such sites actively. The ice and snow is used to move more easily to higher grounds in search of insects in the scree. The ice patches also seem to stimulate play and are used to cool down during warm summer days.

During the late summer of 2013 we picked up a small, inconspicuous and weathered bone from the edge of a melted down ice patch in central Norway. The bone was brought back to the lab and was carefully cleaned and dried. This was in the early phase of collecting faunal remains and closer examination revealed an aspect to these sites that we had not considered much before; the ice patches had been used by more species than just reindeer and humans.

The bone, a shoulder blade from a young reindeer, show clear marks of carnivore gnawing with two conspicuous puncture marks from the fangs. DNA analysis revealed that the animal was closely related to the wild reindeer that live in the area today, while radiocarbon dating show that the calf had died during the late Viking Age (about 1000 years ago). Which animal the gnaw marks belonged to was, however, not clear until we tested it out using the skulls of different predators. Like Cinderella and her shoe, only one animal had a perfect match: the wolverine!

Wolverines typically weigh just between 8 to 18 kg, but like most mustelids, they are powerful hunters capable of taking down prey much larger than themselves, including reindeer. Wolverines typically kill their prey with neck bites, but are known to make shoulder bites as well. As both the front and back of the bone have been pierced at the same time, it is likely that the punctures happened during feeding rather than the kill. No other bones from this site match the age and DNA profile of the reindeer bone, so we are not entirely sure yet who killed the calf. If more bones melt out during this field season we might be able to find out if it was the wolverine or if it was just scavenging on the butchered remains of human hunting.

More info on wolverines:

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The age of old organic remains can be decided through a method called radiocarbon dating or ¹⁴C dating. This is done by measuring the concentration of a radioactive carbon isotope, ¹⁴C, which decays at a regular rate after an organism dies. A detailed description of the method can be found here, but the result is that we get a fairly precise calculation of when the animal died, e.g. 2483 years ago ± 49 years. Thus far, we have dated more than 100 animal remains from glaciers and snow patches in Scandinavia and documented a continuous presence of animals on the ice for more than 4000 years. We don’t know yet how far back we might be able to stretch this timeline as the ice continues to melt and more finds appear. Finds from similar sites in Yukon have revealed more than 9000 year old remains!

Perennial ice and snow cover about 10% of Earth’s land areas and contain most of our fresh water. Despite this, these frozen landscapes are among the least studied ecosystems of the world, especially when it comes to our knowledge about the role of birds and mammals in them. Glaciers and perennial snow patches are currently melting away rapidly and we know very little about which species that are dependent on these areas; even less about how they will be affected by the melting.

Birds and mammals are not normally associated with land ice and such areas are usually excluded when studying animals. However, a recent review of published observations shows that glaciers and perennial snow patches actually are important for many alpine and arctic animals around the world. A relatively large number of birds and mammals actively make use of and spend large amounts of time on glacierized landscapes.

Ungulates and passerines stand out as the foremost users of land ice areas. Relief from summer heat or pestering insects seems to be main reasons that ungulates spend time on glacierized land, while for passerines these areas are mainly used for finding food.

Predators like wolverines, bears and golden eagles are also among the animals that spend time on glaciers and snow patches. In addition to finding food and shelter, birds and mammals use the ice for storing food, for getting water, as playgrounds and as easier traveling routes. One bird, the white-winged diuca finch, even build their nests on glacier ice in the Andes!

In some areas birds and mammals can be important nutrient providers to glacial ecosystems by leaving behind masses of dung, hair, feathers and dead animals.

As the climate gets warmer, the need for glacierized areas will increase for some species, but at the same time these areas melt away and become less available.

Glaciers and perennial snow patches need to be managed properly as threatened ecosystems, but to do this we need to know which species that actually use them and for what purpose. If you have documented such cases, please let us know about it!

For more information:

Rosvold, J. (2015): Perennial ice and snow-covered land as important ecosystems for birds and mammals. Journal of Biogeography (in press).

When gathering data from the ancient remains it is important to know how many individuals we are dealing with. If not, we risk sampling the same individuals several times and could end up piecing together the history in the wrong way.

In many archaeological sites, the bone remains are severely fragmented and also degraded. It is usually very hard to piece together the fragments and infer the number of individual animals in a collection. Scientists have spent decades trying to figure out how to best deal with this problem and have come up with various solutions to statistically infer this number, but often with large uncertainties.

The ice is an excellent medium for preserving organic remains of ancient fauna, but neither here do everything frozen within it stay intact. Large antlers and bones are sometimes broken into smaller pieces, likely due to the pressure of the ice, and scattered over several meters when the ice melts. In contrast to bones found in the soil, the fragments are rarely much degraded. The fragments can thus usually be fitted together fairly easy and reveal a more intact piece of the puzzle.

Most people in northern areas look forward to the arrival of spring and the melting away of the snow. However, some look at the melting snow with sad eyes, wishing that winter would last a bit longer. If you are one of those you are likely a chionophile, and so is the rock ptarmigan (Lagopus muta).

Chionophile means “snow lover”, derived from the old Greek word for snow chion. In biology, a chionophile is an organism that thrives in snow and winter, and that has special adaptations that allow them to survive well in such conditions. For birds and mammals such adaptations include for example white camouflaging coloration, broad feet that don’t sink deep in the snow and dense fur or feathering that protects against the cold.

Like the reindeer, high alpine ptarmigans, like rock ptarmigans and white-tailed ptarmigans (Lagopus leucura), are very well adapted to snow and winter. These adaptations, however, are not that handy when the weather turns hot. As with the reindeer, the ptarmigans are often found close to permanent snow patches during warm summer days. There they can rest on the remaining snow or in cavities under the ice if the temperature gets too high. As an additional bonus, the birds may feed on wind-blown insects that have gotten stuck on the snow patches.

The availability of permanent snow patches is thus an important factor in the habitat of high alpine ptarmigans. Increased glacial melting due to a warmer climate will thus add to the pressures on these species.

That ptarmigans can often be found near snow patches was probably well known to humans far back in time and may have been a factor, in addition to reindeer hunting, that attracted hunters to these sites.

References to ptarmigans and their use of permanent snow and ice:

– Johnson, R. E. (1968). “Temperature regulation in the white-tailed ptarmigan, Lagopus luecurus.” Comparative Biochemistry and Physiology 24: 1003-1014.
– Kaisila, J. (1952). “Insects from arctic mountain snows.” Annales Entomologici Fennici 18(1): 8-25.
– Mann, D. H., et al. (1980). “Diel activity patterns in snowfield foraging invertebrates on Mount Rainier, Washington.” Arctic and Alpine Research 12(3): 359-368.
– Pedersen, Å. Ø., et al. (2014). “Rock Ptarmigan (Lagopus mutus) breeding habitat use in northern Sweden.” Journal of Ornithology 155: 195-209.

In some Native American stories, wolverines are often pictured as the merry tricksters. The wolverine may also play tricks with the interpretation of snow patch finds.

The Latin name of the wolverine is Gulo, which means something like glutton. In Scandinavia, people used to believe that the wolverine were so insatiable that it would keep on eating until its belly became as tight as a drum skin. It would then press its body through a narrow passage between two trees in order to squeeze the food out of its belly. By doing so, it could continue feeding again. In reality, the wolverine takes great care of its food, storing it in different food caches for use in harder times.

Summer is generally leaner times for wolverines, especially for females with cubs. To have access to good food stores is often essential for success. The heat of the summer may cause meat to spoil rapidly, so finding cool places to store food is important. Snow patches are often ideal and it is known that wolverines may cache food in and around them.

Many of the bone finds that melt out of snow patches bear tooth marks of predators and might be the remains of wolverine food caches rather than human hunting. Several finds of nestling birds must have been brought up by some animal as well. It is unlikely that humans brought nestlings up to the snow patches, has the wolverine been afoot?

More info on food caching wolverines:

– Bevanger, K. (1992). “Report on the Norwegian wolverine (Gulo gulo L.).” Small Carnivore Conservation 6: 8-10.
– Inman, R. M., et al. (2012). “The wolverine’s niche: linking reproductive chronology, caching, competition, and climate.” Journal of Mammalogy 93(3): 634-644.

Sampling DNA from ancient bones is an elaborate and time consuming process. Ancient DNA is by definition degraded and due to this special precautions have to be taken. After an animal dies the DNA in its cells quickly starts to degrade and continues to do so over time, leading to loss and fragmentation of DNA. In some bones the DNA is even lost completely. This makes ancient samples prone to contamination from modern DNA and much harder get data from compared to modern samples. Luckily, DNA preserves well in cold environments which makes snow patch finds ideal for studying genetic changes far back in time.

Even so, care has to be taken to avoid contamination and further destruction of the DNA in the bones. That means no snacking on dried reindeer meat while handling old reindeer bones! After they are collected from the snow patches, the finds are slowly dried and then stored in a cooler while they await sampling.

After drilling, the samples are ready for a few days of laboratory work with several rounds of chemical treatments including DNA extraction, PCR and eventually sequencing. The end result is hopefully a nice and clean sequence of nucleotides that provides lots of data,

but with ancient samples some days are better than others…

Due to the excellent conditions for preservation in snow patches, the former is luckily usually the case.

For genetic studies on ancient snow patch finds see:

– Ancient DNA reveals prehistoric habitat fragmentation and recent domestic introgression into native wild reindeer

– Positioning the red deer (Cervus elaphus) hunted by the Tyrolean Iceman into a mitochondrial DNA phylogeny

– Modern and ancient DNA reveal recent partial replacement of caribou in the southwest Yukon

– Preservation of viral genomes in 700-y-old caribou feces from a subarctic ice patch

For some, Christmas is about sparkly stuff; sparkling decorations or sparkling jewelry. For many, Christmas is also about reindeer. Santa wouldn’t be the same without Rudolf and his flock. Snow patches have both, in one and the same: sparkling reindeer! Or at least sparkling reindeer bones.

Vivianite is an iron phosphate mineral that sometimes forms on bones and teeth in waterlogged oxygen poor environments. It is usually white or colorless, but when exposed to oxygen it will turn bright blue. To form, vivianite requires a source of both phosphate and iron. In archaeological settings, human and animal remains with vivianite is usually found in relation to manure deposits or organic waste dumps rich in phospates, in areas with iron rich soils or where the bones have lain close to iron objects.

Vivianite may form as a thin powdery layer that can cover entire bones, or it can form thick crystaline structures. The famous Blue Babe, the Alaskan bison mummy, was largely covered by this mineral. The skin of Ötzi, the ice man, was also covered with vivianite in places that had lain close to the iron rich bedrock beneath.

Only a few of the snow patch bones and antlers have so far been found with vivianite, but the conditions for its formation is good in this frozen environment with slowly decomposing carcasses and large amounts of animal dung. It is, however, still a mystery what the iron source is. Arrowheads?

More on vivianite:

– Vivianite on Wikipedia

– McGowan & Pragnell (2006): The Significance of Vivianite in
Archaeological Settings. Geoarchaeology 21, 93-111.