Péan, who stopped using the material when the New York ban went into effect, said that she appreciated the serious problems facing elephant conservationists but that she believed such trade restrictions were misguided, since trained customs officials could readily distinguish mammoth tusk patterns, the so-called Schreger lines, from those of an elephant tusk. (In contrast, the European Union in July issued a position paper opposing a comprehensive global ban on elephant ivory the existing sales ban expires in 2017.) The action followed similar bans in New York and New Jersey in 2014 and went one step further than the United States Fish and Wildlife Service’s recent efforts to strengthen existing laws on the trade in elephant ivory. The state of California enacted an almost total ban in July on ivory, including that from elephants, mammoths and walruses, in a bid to prevent illegally poached elephant ivory from being passed off as other varieties. Yet with some anti-poaching campaigners working to end ivory consumption regardless of its source, mammoth ivory also is coming under regulation - a situation that the jewelry makers who use it view with concern. Fossilized ivory from woolly mammoths, discovered beneath melting ice caps in Siberia and Alaska, has been touted in recent years as an ethical alternative to elephant ivory, a way to deter the continuing illegal trade in tusks that is threatening an entire species with extinction.