Animals with tusks include elephants, hippopotamuses, walruses, and narwhals.
Tusks are used to produce ivory, which is used in artifacts and jewelry, and formerly in other items such as piano keys.
Since most tusk-bearing mammals are endangered (especially the African elephant), the ivory trade is severely restricted by the United Nations Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). It is unknown if or when this restriction will end.
