{"fact":"Like us, crows find it easier to compare lines that are very different in length. The more similar the lines, the harder it gets!","context":"The crows’ performance improved systematically with increasing relative length differences between the test lines.","source":"Felix W. Moll; Andreas Nieder, The long and the short of it: Rule-based relative length discrimination in carrion crows, Corvus corone\n, 10.1016/j.beproc.2014.08.009","index":205}