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.