Teeth, tusks, and mammoth clues

By Sam Reynolds

A friend of mine produces and sells scrimshaw, engraved artwork on ivory or bone. He makes most of his money at craft fairs. There he patiently explains again and again to mortified fair-goers that the tusks he works on are not from elephants, but from mammoths. “Mammoths that lived at least several thousand years ago”, he politely clarifies—”Not the modern mammoth of today.”

Mammoth ivory—which is sometimes mislabeled fossil-ivory—is by no means ubiquitous. However there is a continuing supply of it, especially from the permafrosts of Siberia, where tusks are often treated as a raw material commodity, not as paleoecological specimens. Mammoth molars and tusks are essentially unregulated largely because they are distinct from contemporary elephant ivory, which is illegal save for a few exceptions. Though still recognizable as ivory, the teeth have often undergone partial diagenesis, consisting of both original and some fossilized material. Sometimes they are preserved nearly perfectly, with little more than staining. In either case, they tend are original material—and provide plentiful and accurate chemical snap-shots of the lives of their proboscidean owners. From a site in Switzerland, Mammoth teeth dated 45,000 years old contained oxygen-18 isotopes that indicated the average air temperature there was 4ºC cooler than today (Heuser, 2010). Teeth can also be analyzed for dietary information through values of carbon-13 and nitrogen-15.

Mammoth tusking showing characteristic banded patterning. Taken from the blog of Charlotte Bailey, a fossil-trader and educator; http://www.rocks-fossils.com.

Continue reading

Small but Mighty: Insects as Proxies

By Wayne Heideman

Insects have been on the Earth for a long time and their presence can affect their surrounding environment. It is important to look at insects in the past as they can provide us with insight on how they can act in the present and in the future. In a paleoecological sense, insects can be studied in a number of ways. One way is to look at plant-insect interactions through plant fossils (herbivory) and peatlands (habitat). Another technique is through amber and observing the insect in a snapshot of time. Lastly, sediment cores in lakes can capture insect presence, notably Chironomidae (non-biting midges) larvae and Coleoptera (beetles). All three are viable means of observing past insect use but they all have their strengths and weaknesses which should be assessed before using a specific method.

A picture of three different types of insect damage on plants. A) Shows a frass trail as well as an oviposition site marked by the arrow. B) Shows a high degree of herbivory, only leaving fine veins and C) shows areas of leaf case shelter sites. From Wilf 2008.

A picture of three different types of insect damage on plants. A) Shows a frass trail as well as an oviposition site marked by the arrow. B) Shows a high degree of herbivory, only leaving fine veins and C) shows areas of leaf case shelter sites. From Wilf 2008.

Continue reading