Illegal trade in animal parts is a global problem that's signaling the extinction for many endangered species. Experts estimate that about 25,000 elephants were killed last year alone, for their ivory tusks. The driving economic forces that facilitate the illicit trade are supply and demand.

In this short video, we travel to China, where investigative journalist Bryan Christy explains how a longstanding tradition of carving ivory, combined with a booming middle class, is fueling demand for ivory. The Convention on International Trade in Endangered Species (CITES) reports that nearly all of the current demand for elephant ivory comes from the Chinese market. The International Fund for Animal Welfare estimates that 84 percent of the ivory sold in China is illegal.

Then, in east Africa, we follow investigative journalist Aidan Hartley as he goes undercover to learn first-hand about the rising prices of black market ivory. Using specialty cameras to infiltrate the criminal network, Aidan documents the illegal supply leaving Africa.

This video was produced to accompany the National Geographic film Battle for the Elephants, which explores the history of and economics behind the brutal slaughter of African elephants for their tusks.