{"fact":"Crows can remember the faces of dangerous people for at least five years.","context":"Learning enabled scolding to double in frequency and spread at least 1.2 km from the place of origin over a 5 year period at one site.","source":"Heather N. Cornell; John M. Marzluff; Shannon Pecoraro, Social learning spreads knowledge about dangerous humans among American crows, 10.1098/rspb.2011.0957","index":259}