Colors to highlight

The combination of striking colors in nature is technically known as “aposematism” and it is used by animals as a warning signal to keep predators away. It is present in the spectacular South American frogs of the genus Dendrobates, secretors of a potent cutaneous venom. Yellow and black wasps and red and black heteroptera are aposematic insects, dangerous due to their bites or their venom. Humans use aposematism in the design of the war shields of several African tribes, in the military clothing of the eighteenth century, or in the flags of the countries. And a beautiful example is found in Barcelona’s taxis. The combination of yellow and black is obviously not a warning sign, but it stands out in the middle of traffic and facilitates the location of vehicles.