An evolutionary strategy, in which some members of a species gain an advantage over others by not conforming to the social norm. For example, alarm signals incur a cost in attracting the attention of a predator to the individual giving the alarm. All members of a group benefit from the alarms given by colleagues, but the situation is open to cheating. It might pay an individual to save time and reduce risks by reducing the time it spends being vigilant in a group situation. Some species have mechanisms that reduce this possibility. Pigeons (Columbia livia) feeding in a flock give a special intention signal when they are about to depart. If they depart in a hurry, without giving this signal, then all the other birds fly off in alarm. Thus the vigilant pigeon, by flying away without giving the ‘goodbye’ signal, is warning the other members of the flock, yet it gains an advantage by flying away first. This type of cheating is assumed to be genetically based, and it occurs in a wide variety of situations, including courtship, feeding, and fighting.
Subjects: Zoology and Animal Sciences.