Reminds me of Calhoun's Mouse Utopia experiments: "Other young mice growing into adulthood exhibited an even different type of behavior. Dr. Calhoun called these individuals “the beautiful ones.” Their time was devoted solely to grooming, eating and sleeping. They never involved themselves with others, engaged in sex, nor would they fight. All appeared [outwardly] as a beautiful exhibit of the species with keen, alert eyes and a healthy, well-kept body. These mice, however, could not cope with unusual stimuli. Though they looked inquisitive, they were in fact, very stupid."

https://fee.org/articles/john-b-calhoun-s-mouse-utopia-exper...