Ivory is also preserved in the tundra of Siberia, northern Canada and other polar regions where prehistoric mammoths roamed the continents thousands of years ago. Some of these tusks are larger than the tusks of mammals that exist today. However such fossil ivory is harder to carve.
Walrus tusks are especially popular in North America, where they were used by Native Americans for hundreds of years.
Today trading ivory from elephants and other endangered animals is illegal. During the 20th century large parts of the elephant population were reduced because of ivory trade. The poached ivory is smuggled out of the country and sold at a very high price.
Since the end of the 20th century governments of African and Asian countries have focused on capturing poachers and clamping down on illegal trading rings. Tons of ivory are seized by authorities every year. In the last few years these actions have stabilized the elephant population. Some countries have put elephants into reserves, where they can be closely monitored.