Zookeepers now have a new challenge for their gorillas: limiting the time they spend near smartphone screens.

According to the publication Wall Street JournalZoos across North America are trying to curb a smartphone obsession with animals that has become evident in recent years as more and more visitors have begun viewing animal pictures and videos on screens through the glass walls of their enclosures.

Over the past few years, reports have begun to emerge in major urban zoos that gorillas are often fascinated by seeing their images on smartphone screens, becoming obsessed or even “addicted” to these devices.

For example, last year in Toronto, zoo staff began hanging posters urging visitors not to point their smartphone screens at the animals; the animals are often so enamored with them that their behavior begins to change, as the monkeys tend to spend more and more time in front of their smartphone screens.