The English version of the Chinese website People’s Daily reports:

Scientists spot first tool usage in wild gorilla

Scientists photographed for the first time ever [a wild gorilla using] a stick to test the depth of a pool before wading into it, according to a study appearing in Friday’s journal Public Library of Science (PLoS) Biology.
Up to this point, all other species of great apes including chimpanzees and orangutans, have been observed using tools in the wild, but never gorillas. Scientists said this new finding is ‘astounding.’ …The observations were made in Mbeli Bai [Congo], a swampy clearing located in Nouabale-Ndoki National Park where monitoring has been ongoing since February 1995. The first instance occurred when a female gorilla nicknamed Leah by scientists attempted to wade through a pool of water created by elephants, but found herself waist deep after only a few steps.
Climbing out of the pool, Leah then retrieved a straight branch from a nearby dead tree and used it to test the depth of the water. Keeping her upper body above water, she moved some 10 meters out into the pool before returning to shore and her wailing infant.”