Anim. Cogn. 11, 683–689 (2008)

Honeybees (Apis mellifera) can count up to four — giving them another string to their navigational bow. Working at the Australian National University in Canberra, Marie Dacke and Mandyam Srinivasan trained the insects to fly down a tunnel in search of food placed beside one of five identical landmarks positioned at intervals.

When trained bees flew into a tunnel that had no food, they searched most at the previously rewarding landmark — unless it was number five.

Moving the landmarks nearer to or farther away from each other did not fool the bees, showing that they were not relying on distance, but were counting the number of landmarks before the food. Changing landmarks from stripes to spots had no effect either, suggesting that bees can use numbers in an abstract way.