Most countries have laws to protect their endangered species, and do not let them be killed for making medicines or jewellery, or to be smuggled out of the country for pets.

Animal smugglers often kill the animals they try to get out of the country, because they have to hide them from the people in customs. Often the animals die because their new owners don't know how to look after them.

Elephants have been killed just to get their tusks, and rhinos, just to get their horns. Then the bodies are left to rot, because the hunters don't get money for them.

If people stopped buying ivory (which is what we call things made from elephant tusks) and medicines from parts of rare animals (like rhino horns), the hunters and animal smugglers would not be able to sell them, and they would stop killing them.