Contact calls

Seemingly haphazard sounds made by many social animals (like chicken cluck) are known as contact calls.^[1] Contact calls are very different from many other types of calls (for example, alarm calls), as contact calls are not a specific signal, designed to communicate some specific information. It is rather a mixture of various sounds, accompanying the group's everyday business (for example, foraging). Contact calls are used to maintain audio contact with the members of the group. Some social animal species communicate the signal of potential danger by stopping contact calls, without the use of alarm calls. Charles Darwin wrote about this in relation with wild horse and cattle.^[2]

Humming as contact calls

Joseph Jordania suggested that human humming could have played a function of contact calls in early human ancestors.^[3] According to his suggestion, humans find distressing being in full silence (which is the sign of danger for them) that's why humans hum, whistle, talk to themselves, have TV and radio on sometimes without watching or listening to them.

References

1. ^ Macedonia, J. (1986). Individuality in the contact call of the ring-tailed lemur (Lemur catta). American Journal of Primatology, 11, 163-179
2. ^ Charles Darwin (2004). The Descent of Men. London: Penguin Books. pg. 123. 
3. ^ Jordania, J. (2009). Times to Fight and Times to Relax: Singing and Humming at the Beginnings of Human Evolutionary History. Kadmos, 1, 272–277

See also

• Humming
• Singing
• Animal communication
• Whistling
• Silence