Article in the Corriere della Sera ... mica blogospera last blog, you know?

Short, it seems that the fish in question, Gambusia holbrooki, are able to "numeracy" and make choices based on the number of individuals of the same species that come before them. The research was carried out at Padova and shows how the small fish are able to choose the larger group to which clump together, but only if the total number of fish in the group is less than 4, more than 4 should be selected at random in the ball and ... sometimes find the largest group ... many others do not.