https://www.newscientist.com/article/2314938-dogs-use-fast-acting-face-muscles-to-help-them-make-puppy-dog-eyes/

Dogs use fast-acting face muscles to help them make puppy-dog eyes

Dogs have more “fast-twitch” muscle fibres around their eyes and mouths than wolves do, which allows them to make more facial expressions

https://www.newscientist.com/subject/life/

5/4/22