A study has revealed that predators tend to avoid prey that look different from the rest of the population, which helps rare traits survive.

A team of biologists led by Benjamin Fitzpatrick from the University of Tennessee used dummy salamanders filled with feed with either striped or not striped skin to study the behavior of a flock of Blue Jays. The proportion of the two kinds of ‘prey’ was nine-to-one, and the scientists maintained the supply for six days in a row. The choice of the prevalent kind of prey was different in each case.

Then on test day they changed the proportion to one-to-one. The birds were more likely to attack the models, which were more common during the previous period. As it turned out, the actual skin pattern was irrelevant, only the rarity of the coloring in the days before the test day.