The illegal slaughter of African elephants to feed Asia’s demand for ivory has decreased by more than half in eight years, but the majestic mammals are still threatened with extinction, researchers warned on Tuesday.

“An elephant tusk is actually the elephant’s tooth of which more than one-third of the tusk, or its palatal root, is rooted in its jaw. That means, removing an elephant’s tusks without causing the death of the animal is almost impossible.