If you asked average Grade 6 students about animals that lived in the geological past the chances are that they would talk about dinosaurs. However, I am sure that following close behind would be some contemplation of those fabulous "Ice Age" mammals the mammoths and the mastodons. I'm not sure why this should be the case - perhaps because they are commonly illustrated in text books, or because they appear as imposing skeletons in many museums, or perhaps, because they can be related to our African and Indian elephants commonly seen in zoos. I would hesitate to suggest that there might be a racial memory of facing these huge animals lodged somewhere in our genetic inheritance, and yet this is exactly what our ancestors had to do, 10,000 to 20,000 years ago. How do we know this and what proof do we have that humans and mammoths (and mastodons) co-existed?
There is good archaeological evidence that mammoths and humans lived at the same time in the Northern Hemisphere, particularly as the continental ice sheets were melting from Asia, Europe and North America, and equally good evidence that paleo-Indian hunters killed mastodons in North America. This evidence is present in the form of cave paintings from Europe, for example in caves in south-western France, northern Spain, from the southern Urals and from many other sites. Illustrations and carvings of many of the "Ice Age" (Pleistocene) mammals show that our prehistoric ancestors not only knew these animals, but also hunted them for food. Huts made from hundreds of mammoth remains in Siberia suggest how the remains of these large elephants were utilised. Carvings of mammoth ivory or mammoth "sketches" on bones also link the human hunters with the hunted. In North America the remains of mastodons in many different sites illustrate that these New World elephants of the latest Pleistocene were also hunted.
We know a great deal about mammoths because their remains are preserved in the permafrost of Siberia and Alaska. Several well-preserved carcasses from northern Russia have allowed us to examine these frozen remains in some detail. Over the course of three decades I have encountered a number of skeletal mammoth remains in Europe, and in the last ten years my research area has brought me into contact with a number of colleagues who are examining mastodont and mammoth sites in the Great Lakes region. In this article I would like to comment on the differences between mammoths and the mastodons and on the distribution of finds in southern Ontario, illustrating where these remains are most often found. I'd also like to briefly describe how our research on fossil insect remains has helped to build a picture of the environments occupied by these two rather different elephants.
Be aware that there are many more sites with large concentrations of bones of these animals, such as those at salt licks or at the karst sinkholes in Missouri. These are not mentioned in this note.
First, let me mention that there are several different species of mammoth and mastodon. In this summary I will only be commenting on the "Woolly Mammoth", Mammuthus primegenius, and the "American" mastodon, Mammut americanum. Both of these animals flourished in the latter part of the Pleistocene Epoch which ended about 10,000 years ago. Like many of their "Ice Age" counterparts, such as the Giant Sloth, the Cave Bear, the Short-Faced Bear, the Cave Lion, and the Eurasian Woolly Rhinoceros, they generally vanished within a matter of perhaps 5,000 years at the start of the current warm period which we know as the Holocene. This was the time that humans became truly organised, and one cannot but help feel that the combination of rapid climate change, shrinking and changing habitats and the new, efficient tool-equipped hunter, Homo sapiens, was just enough to tip the balance against these very large mammals. In the case of the mammoths, we missed them by a cosmic eyeblink. The latest research from northern Russia indicates that a small herd of mammoths was alive at the time that the first pharaohs were ruling Egypt (Vartanyan, et al., 1993).
There are approximately 120 finds of mammoths and mastodons in southern Ontario, and many more than that if you take in the adjacent American states of Michigan, Indiana, Ohio, Pennsylvania and New York. About 90 of these discoveries post-date the retreat of the last ice in this region about 14,500 years before present (yr. B.P.). Nearly all of these finds are associated with three types of deposits; a few are found as isolated remnants in sand and gravel deposits, possibly when animals were drowned, or when their remains were washed by meltwater rivers to their final resting place. Other isolated bones have been found in glacio-lacustrine sequences, again probably where the carcasses or bones were washed into various glacial lakes which were so common in southern Ontario during ice recession. The vast majority, however, are associated with hollows generally unfilled with shelly marls or peat.
Most of the finds which are reported to museums are made when local farmers attempt to drain marshy depressions, or have tried deep ploughing in a peaty corner of the field which had not previously been worked. The remains which are brought to our attention generally consist of three skeletal elements, tusks or tusk fragments, bones (some of which can be very large), and teeth (which may, or may not, be still in-place within the jawbone). Of these the teeth are by far the most useful. Generally the tusk remnants are badly fragmented. There is a difference between a mammoth and a mastodon tusk. The former has a "double curve" which swings the tusks out and away from the trunk, and then back into the centre; the latter has a slightly-curved tusk. In most cases the curvature is a moot point since the tusk materials are often fragmented, delaminated or badly eroded. The bones are useful in suggesting that they belong to an elephant, rather, than say, to a horse, a cow, or a large deer. The teeth are, however, quite diagnostic. The mammoth had teeth which are very similar to the teeth of the Indian or African elephant, consisting of a number of lamellar "plates" stuck together in parallel sheets. This is particularly well seen from above where the tooth has a "banded" appearance. The mastodon has "mammalated" teeth, with a number of cusps which produce a "knobbly" appearance.
In southern Ontario most of these large elephants are found in peaty depressions which mark the site of former ponds and small lakes. In examining the remains of these animals it is possible to say that this type of habitat probably was preferred by the mastodon. Mastodon remains far outnumber mammoth remains in these sites. The dentition of the mammoths suggest that they were open ground grazers which occasionally became trapped in marshy depressions when they came to drink, or perhaps when they broke through winter ice. The mastodons probably preferred a more forested environment and may have preferentially grazed on a number of aquatic plants, becoming trapped on a more regular basis when they broke through floating mats of vegetation extending out over softer, marly sediments. One other factor, suggested about a decade ago by Professor Dan Fisher at the University of Michigan, is that some remains found in bogs were deliberately placed there by human hunters who used the cold and acidic waters as a natural refrigerator, returning to the site to snack on the gradually "maturing" remains!
Less you think that this last hypothesis is rather far-fetched, Dr. Fisher has evidence in the form of cut-marks on bones, disarticulated skeletons which must have been stached by humans, and stone "sinkers" which were used to weight the carcass. To top this off, he has experimented by sinking the remains of a large draught horse in a small bog in Michigan, and then consuming portions of the meat over a period of more than six months. I'm pleased to say that he survived this experiment, and I'm hoping that we can have a personal account of his experiences sometime in a later issue of Wat On Earth!
Our experience in examining the fossil insect remains associated with these sites reveals an environmental "picture" substantiated by plant remains and pollen. We have examined one mammoth site, the Rostock site, near Stratford, Ontario. Here the mammoth remains are dated to about 10,600 yr. B.P., at the time when vegetation was starting to change from spruce to pine trees. The beetles in this site indicate that the area was still relatively open and a number of prairie (western) beetles in the sequence suggest that grasses and sedges were present near the site. The mastodon sites examined (Powers, Heisler and Shelton in Michigan and Burning Tree in Ohio) are more indicative of bogs in spruce and pine dominated forest areas. There were numerous aquatic insects in these sites indicating the presence of floating plants such as water lilies as well as numerous sedges, and there is a suggestion that the vegetation cover was more diverse and luxuriant than at the Rostock site.
For those interested in reading more on the topic of mammoths and mastodons in southern Ontario and the adjacent United States, there are several papers which are of interest. I have outlined a few of these below.
Agenbroad, L.D. 1984, New World mammoth distribution, p. 90-108. In P.S. Martin and R.G. Klein (eds.), Quaternary Extinctions: A Pre-historic Revolution. University of Arizona Press, Tucson.
Ami, H.M. 1898. The mastodon in western Ontario. Science, 7:80.
Dreimanis, A. 1967. Mastodon, their geologic age and extinction in Ontario, Canada. Canadian Journal of Earth Sciences, 4:663-675.
Dreimanis, A. 1968. Extinction of mastodons in eastern North America: testing a new climatic-environmental hypothesis. Ohio Journal of Science, 68:257-272.
Drumm, J. 1963. Mammoths and mastodons, ice age elephants of New York. New York State Museum and Science Service, Educational Leaflet, 13:1-29.
Fisher, D.C. 1984(1985). Taphonomic analysis of late Pleistocene mastodon occurrences: evidence of butchery by North American Paleo-Indians. Paleobiology, 10:338-357.
McAndrews, J.H., and L.J. Jackson 1988, Age and environment of Late Pleistocene mastodont and mammoth in southern Ontario. 161-172 In: Late Pleistocene and Early Holocene Paleoecology and Archaeology of the Eastern Great Lakes Region. (eds. R.S. Laub, N.G. Miller and D.W. Steadman. Bulletin of the Buffalo Society of Natural Sciences Volume 33.
Shipman, P., D.C. Fisher, and J.J. Rose. 1984 (1985). Mastodon butchery: microscopic evidence of carcass processing and bone tool use. Paleobiology, 10:358-365.
Skeels, M.A. 1962. The mastodons and mammoths of Michigan. Papers of the Michigan Academy of Science, Arts and Letters, 47:101-126.
Vartanyan, S.V., Garutt, V.E., Share, A.V., 1993. Holocene Dwarf Mammoths from Wrangel Island in the Siberian Arctic. Nature 362:337-340.