BEIJING, April 3, 2016 (Xinhua) -- Sumatran elephants (Elephas Maximus Sumatranus) are trained by trainers at the Elephant Conservation Center in Aceh, Indonesia, March 27, 2016. World Wildlife Fund (WWF) announced in 2012 that the Sumatran elephant has been downgraded from "endangered" to "critically endangered" by the International Union for Conservation of Nature (IUCN) after losing nearly 70 percent of its habitat and half its population in one generation. The decline is largely due to elephant habitat being deforested or converted for agricultural plantations. (Xinhua/Junaidi)