A critically endangered elephant species has been photographed by researchers for the first time in South Sudan, significantly expanding the known range of the animal. But even in these remote central African forests, it faces threats from illegal logging and from war.

Smaller than savanna elephants, the forest elephants roam tropical forests and were photographed by cameras tied to trees.

"This is by far the most northerly herd of forest elephants that anyone has seen in Africa," said Adrian Garside, a leader of the study by Fauna and Flora International.

Forest elephant populations declined by 60 percent between 2002 and 2011, according to a 2013 study published in scientific journal PLOS ONE. - AP