Scientists from Oxford Brookes University, England, looked at hundreds of Instagram posts from people visiting the animals in East Africa and found most tourists were close enough to gorillas to spread viruses and diseases, according to a press release from the university on Tuesday.
"The risk of disease transmission between visitors and gorillas is very concerning," said study lead author Gaspard Van Hamme, an Oxford Brookes University alumnus who started work on the study during his masters program.
"It is vital that we strengthen and enforce tour regulations to ensure gorilla trekking practices do not further threaten these already imperiled great apes."
Mountain gorillas are listed as endangered, with an estimated 1,063 of them left in the wild, according to the release.
They live in the Democratic Republic of Congo (Virunga National Park), Uganda (Bwindi Impenetrable National Park and Mgahinga Gorilla National Park), and Rwanda (Volcanoes National Park).
Researchers looked at 858 photos posted on Instagram from 2013-2019 under two hashtags -- #gorillatrekking and #gorillatracking, said the study. Of that number, 86% showed people within four meters (13.1 feet) of gorillas, and 25 of those photos showed tourists touching gorillas.