lem·ming 
/ˈlɛmɪŋ/ noun
plural lem·mings /ˈlɛmɪŋ/ noun [count] : a small animal that lives in northern areas of North America, Europe, and Asia ◊Lemmings sometimes form large groups that move together. According to legend, these groups sometimes march into the sea, where large numbers of the lemmings drown. Because of this, people are sometimes said to be acting like lemmings when they do something that is harmful or stupid because other people are doing it.
