“China is a vacuum cleaner for Siberian wildlife,” said Aleksei L. Vaisman, a senior coordinator for Traffic Europe-Russia, which is sponsored by the conservation group WWF, which monitors trade in wild animals. The largest cache of bear paws he knew of previously was 787 paws (one paw shy of 197 full sets of four).

As Russian border agents using dogs have become more adept at catching small-time traffickers, smugglers have been compelled to risk large shipments, he said. The large number reported Tuesday (from about 260 bears) were most likely accumulated by brokers who bought them from hunters over the winter, he said. A set of four brings the hunters about $50.

Bear paws are a ritual dish for Chinese, elk lips a delicacy. Also smuggled daily, for food or medicine, are bear gallbladders, frogs, deer antlers and the genitals of spotted deer. The bones of highly endangered Amur tigers are sought for their aphrodisiac qualities.

The mammoth ivory poses an unusual set of legal and ethical issues.

The tusks are more abundant than many people in the West realize. Encased in an upper layer of Siberia’s permafrost are the remains of an estimated 150 million mammoths that lived from 3,600 to 400,000 years ago. The parts surface in the spring thaw across vast stretches of Russia’s far north and are routinely collected. Most are exported — legally — to China, South Korea and Japan to be carved into personal stamps used in place of signatures on documents.

Russia, though, requires an export license. This is intended to ensure that traders send tusks with possible scientific value — like prehistoric slaughter marks or signs of ancient disease — to researchers. Generally, conservationists concerned about the illegal ivory trade from Africa into Asia encourage buyers to turn to the legal trade from Siberia of ivory from mammoths.