The thawing of the Russian permafrost is exposing tons of bones of woolly mammoths that were locked in frozen mud for thousands of years. Interestingly, they seem to have been trapped in ice after the glaciers retreated: after the last ice age. Thet means the glaciers retreated, the mammoths lived on unfrozen ground, died and were frozen, then stayed trapped in frozen ground for 10,000 years or so. It kind of fits with my own theory that the climate can change radically within a short period, and that the melt of the glaciers in a very short period of intense warmth was followed by the period of extreme cold in the Arctic that is now coming to an end. The freeze-dried forests and preserved dams of giant beavers on Canada's arctic islands point to that type of change.
Mammoth bones and teeth are interesting, and the sell for a few bucks on the open market for fossils. (And anyone who wants to see that in action should visit the city-wide Tucson, Arizon show in February). The tusks are worth much more, as decorator pieces or, if busted up, as sources of legit natural ivory.
The ivory will alsways be worth money. The market for bones should be sated quite quickly. How many people have the inclination, or the physical space, to have a woolly mammoth or parts there-of around the house. (This comes from a guy who has about a ton of trilobite fossils).
The guys at Canada Fossils have been legally exploiting this Siberian material for years, from even before the fall of the Soviet Union. Since 1990, the trade has really taken off, as this article in a Sydney, Australia, paper shows.