The “bystander effect” can influence humans – and now it seems rats as well – not to step in to help another, but only if the bystanders are emotionally uninterested in what is happening
Source:
https://www.newscientist.com/article/2248324-rats-will-help-others-in-distress-but-they-can-be-influenced-not-to/?utm_campaign=RSS%7CNSNS&utm_source=NSNS&utm_medium=RSS&utm_content=home