Of course, organisms have evolved to use encoded signals within the species as well. Encoded
signals can be interpreting natural signs or direct communication. Migrating birds, for instance, often respond to changes in seasonal weather, the positions of the sun and stars to commence annual long distance treks.Anomalous animal behavior has often been observed with the onset of significant natural events such as earthquakes. Birds, fish, and mammals may be capable of interpreting environmental cues that have eluded us in recognizing such events. Some animals respond to the shortening days, reduced sunlight, and decreasing food supply as signs inducing hibernating behavior. Reversing these cues can bring the same species out of hibernation.