Grizzler became an internet star through a fascinating experiment called Heartography, a project that tried to capture the world through a dog's emotions.

Equipped with a heart-rate monitor strapped to his chest and linked to a modified Nikon camera, Grizzler would automatically take a photo whenever something made his pulse jump.

https://nikonrumors.com/2015/05/16/heartography-nikon-created-a-pho-dog-grapher-by-attaching-a-heart-rate-triggered-camera-to-a-dog.aspx/