Researchers document huge drop in African elephants in a half century

African elephants are Earth’s largest land animals, remarkable mammals that are very intelligent and highly social. They also are in peril.

African elephants are Earth's largest land animals, remarkable mammals that are very intelligent and highly social. They also are in peril. Fresh evidence of this comes in a study that documents alarming population declines at numerous sites across the continent over about a half century.

Researchers unveiled on Monday what they called the most comprehensive assessment of the status of the two African elephant species - the savanna elephant and forest elephant - using data on population surveys conducted at 475 sites in 37 countries from 1964 through 2016.

The savanna elephant populations fell by about 70% on average at the surveyed sites and the forest elephant populations dropped by about 90% on average at the surveyed sites, with poaching and habitat loss the main drivers. All told, there was a 77% population decrease on average at the various surveyed sites, spanning both species.

Elephants vanished at some sites while their populations increased in other places thanks to conservation efforts.

"A lot of the lost populations won't come back, and many low-density populations face continued pressures. We likely will lose more populations going forward," said George Wittemyer, a Colorado State University professor of wildlife conservation and chair of the scientific board of the conservation group Save the Elephants, who helped lead the study published in the journal Proceedings of the National Academy of Sciences.

Poaching typically involves people killing elephants for their tusks, which are sold illegally on an international black market driven mostly by ivory demand in China and other parts of Asia. Agricultural expansion is the top factor in habitat loss.

The forest elephant population is estimated to be about a third that of savanna elephants. Poaching has affected forest elephants disproportionately and has ravaged populations of both species in northern and eastern Africa.