LOUISVILLE, Ky. (WISH) – Video of an interaction between a gorilla and a zoo visitor has been viewed by millions of people in a matter of days.

It was posted on Sept. 6 by Paul Ross. In the video, a man sits close to a window of the Louisville Zoo Gorilla Forest where a gorilla is sitting.

He holds his phone up to the glass and shows the gorilla images of other gorillas. As he flips through the pictures, the primate appears fascinated, and even scoots closer to the phone.

According to the zoo’s website, all of the gorillas there are Western lowland gorillas, a species classified critically endangered by the International Union for Conservation of Nature (I.U.C.N.).

The award-winning facility opened in 2002.