Buzz
Animals like zebras have coat patterns, such as stripes, which help them blend into their surroundings or merge with others of the same pattern. This camouflage makes it difficult for predators to spot them or focus on a single individual in a crowd of similarly patterned creatures. A consistent pattern is key to this blending, but how do these seemingly purposeful patterns appear on an animal’s fur?
Alan Turing, the mathematician who deciphered the Enigma code, uncovered how regular patterns are formed through a combination of processes that work at both long and short ranges. Imagine a room with walls filled with different-sized holes. A line of people attempts to pass through these walls. The short individuals easily move through the smaller holes, while the taller ones are restricted to the larger ones, moving more slowly. Tall individuals also try to help each other, while the short ones attempt to hinder the tall ones from advancing. Over time, tall people gather near the initial walls, slowed by the size of the holes and the short people, but their numbers grow as they help each other. Meanwhile, short individuals move freely, unimpeded by the walls.
If the short and tall individuals were dressed in distinct colors—white for the short and red for the tall—an aerial view of this process would show a regular pattern of red patches where the taller individuals have accumulated. This process mirrors the way coat patterns are created. Chemical 'activators' (the tall people in this analogy) promote pigment production in certain areas, while 'inhibitors' (the short people) move quickly, preventing the pigment from spreading too far.
The formation of regular patterns is not confined to animal coats. Both long-range and short-range processes create predictable patterns in mussel beds, plant life, and even microscopic organisms. In these systems, species benefit from proximity to others of the same kind at close distances, but competition among individuals limits their spread at greater distances.
Monica Granados is pursuing her PhD in Biology at McGill University.
