There was a time when it was thought that tool use was the singular ability of humans and their captive primate prodigies. Then wild chimps were observed using sticks and stones to dig out termites and crush nuts. Evidence that wild bonobo monkeys and orangutans exhibited related behaviors soon followed. Now a team led by the Wildlife Conservation Society's Thomas Breuer has the first photographic proof that wild gorillas in the Republic of Congo are a handy lot as well – Breuer watched one gorilla use a stick to sound out depth before wading through water, and another using a branch to bridge a puddle. Most tool use in great apes is related to food gathering, but researchers say the gorillas' stick fording may actually be more indicative of abstract reasoning. More from PLoS Biology.