Editor’s note: On August 25, the proposal to restrict trade of long-extinct woolly mammoths by adding the species to CITES Appendix II was withdrawn when it became clear it would not pass. Read more details about the vote here.

One of the most surprising proposals under discussion at the giant global wildlife trade treaty meeting in Geneva, Switzerland, is about woolly mammoths—creatures that once wandered huge tracts of North America, Europe, and northern Asia—and went extinct more than 4,000 years ago.

The move to consider adding an extinct species to the list of living, regulated animals is controversial, since the objective of the CITES treaty is to help prevent species today from being driven to extinction because of the international trade in wildlife products. The treaty doesn’t specifically preclude the listing of extinct species, but it does state that they “should not normally be proposed for inclusion.”

The reason for the proposal, which was submitted by Israel? To clamp down on elephant ivory smuggling.

“Since mammoth ivory trade is almost totally unregulated and undocumented, and because mammoth ivory is not easily distinguished from elephant ivory, there is a tangible risk of illegal international trade in elephant ivory being facilitated by deliberately mislabeling specimens of elephant ivory as mammoth ivory in order to avoid the requirements of this Convention,” the proposal explains. (Learn more about the ivory trade: under poaching pressure, elephants are evolving to lose their tusks.)

Worked ivory from woolly mammoths and elephants have few physical differences. One difference, often invisible to the human eye: Mammoth ivory has an iron phosphate called vivianite, which can cause blue-green or brownish blemishes. Otherwise, the ivories are largely identical. Whole mammoth tusks, though, are easily identified because—unlike those of elephants—they grow in spiral form, resembling a corkscrew.

As permafrost has melted in recent years, woolly mammoths long trapped beneath the ice are now increasingly accessible in Siberia, and Russia has become a major exporter of mammoth ivory—a substance sometimes called ice ivory.

Between 1993 and 2003, more than 22,000 whole tusks from woolly mammoths and 500,000 carvings were imported into the United States, according to data from the U.S. Fish and Wildlife Service Law Enforcement Management Information system. Meanwhile, analysis from the International Union for Conservation of Nature and the wildlife trade monitoring group Traffic notes that, “Evidence from mainland China, Hong Kong SAR, Myanmar, and the USA suggests that some vendors are mislabeling elephant ivory as mammoth ivory, but there is no comprehensive assessment to suggest how widespread this practice is.”

Israel originally decided to put forward this mammoth proposal in partnership with Kenya (which, unlike Israel, has elephants to conserve). The two countries have worked together in the past on conservation issues, and Israel has helped train some Kenyan rangers over the years, says Simon Nemtzov, Israel’s CITES scientific expert and head of international affairs at the Israel Nature and Parks Authority. But Kenya missed a deadline along the way, leaving Israel as the only official sponsor.

“We proposed already at the last CITES meeting three years ago to encourage parties to stop the trade in mammoth,” Nemtzov told National Geographic in an interview in the months leading up to the conference.

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“Now, we’re going one step further to have mammoth listed in Appendix II, which would not ban trade but would require registration of all this trade.” It would mean that before an export permit can be issued, “the exporting country has the onus to prove it’s really mammoth ivory.” (The treaty, however, doesn’t lay out a verification protocol.)

Nemtzov said the proposal could succeed because provisions exist under CITES to list an extinct species if it’s a look-alike of a living endangered species, but he expects Russia, as the main mammoth ivory exporter, to oppose it.

“Right now, mammoth ivory doesn’t go through the CITES system so there’s no good information on what’s being traded, and where it’s coming from,” Nemtzov said. “The idea is to keep track of it, and an appendix listing will allow that to happen."

If the proposal passes, delegates from the 183 parties to CITES would essentially treat Mammuthus primigenius—which last walked the earth in the early Holocene—as an endangered species, with necessary trade restrictions.