The growing international ban on the trade of ivory from elephant tusks has been increasing the focus on harvesting the illicit material from an unusual source: the tusks of long-extinct mammoths, preserved in the frozen Siberian tundra. Out of the 72 tons of mammoth ivory exported by Russia in 2017, 80 percent was to China–the world’s largest market for the substance–and now that China has instituted a ban on their ivory trade, the market for frozen mammoth tusks may be heating up.

Collectors of this prehistoric ivory are concentrating their harvesting efforts on Russia’s Yakutia region in northern Siberia, a landscape dominated by permafrost, permafrost that has preserved the corpses of animals from species of lions, wolves, horses, caribou–some of which have been extinct for tens of thousands of years. The preservation of ancient mammoth carcasses is no exception, with some of the bodies being preserved well enough for scientists to extract DNA from.

Of course, this deep-freeze has also preserved the more robust tissues of these animals, including the tusks of the mammals that bore such structures, meaning ivory hunters can harvest tusks that are just as good as ones from extant animals, but without having to actually kill an endangered animal, and the legal trouble that such an act can bring.

There are an estimated 150 million mammoth carcasses frozen in the Siberian tundra, far more than the 500,000-750,000 individual elephants estimated to be alive today, representing an estimated 550,000 tons of ivory available for trade. Although this is a finite resource (at least until someone starts cloning the creatures), this supply could keep those with a thirst for ivory well stocked for a long time to come, without having to contribute to the continued predicament faced by our pachyderm population.

While it is legal to trade in ivory obtained from mammoths, there is still little regulation governing the harvesting of the tusks, although licenses to do so are issued by the Russian government. Access to Yakutia’s remote tundra is also difficult, with few roads servicing the region’s 3 million square kilometers (1.2 million square miles, an area more than twice the size of Alaska), meaning that harvesting expeditions need to be well equipped. These factors make for a high-priced product when it hits the streets, often selling for roughly $450 per pound. Regardless of the difficulties, the ice ivory trade has become a valuable source of income for people in northern Yakutia, where jobs are scarce.

But there is a potential downside to this new guilt-free ivory trade, as it can require the excavation of fragile Arctic permafrost, with some larger expeditions using water jets to melt holes in the tundra. But most collectors are locals that simply gather the tusks when they encounter them on the surface, without having to dig into the earth to bring them to market. Moscow introduced a bill that would fully regulate the industry in 2013, one that would prevent large-scale operations from harming the tundra while protecting individual collectors, but six years later this bill remains unaddressed by Russia’s parliament.