Bettmann/Getty Images
Why do we scream in fear? It doesn’t help and it makes us more vulnerable to predators.
Mike Follows
Sutton Coldfield, West Midlands, UK
Screams evolved as alarm calls to alert other members of a group to potential danger, particularly among social species. Screams are especially effective when a predator or a rival group is relying on stealth to launch an attack. Although screaming can make an individual more conspicuous, such warnings increase the likelihood that the group can respond, mount a defence or ensure that at least some members – often close relatives – survive. In this way, screaming supports the survival of the group as a whole.
Indeed, researchers Katie Slocombe and Anne Schel led a study of vocalisations among chimpanzees (Pan troglodytes) in Uganda and found that the animals directed alarm calls towards close friends or allies who were being approached by an artificial python.
Screams can also disrupt or deter predators by signalling that the prey is alert, healthy and difficult to capture, or by attracting other predators or competitors that the attacker may wish to avoid. In addition, screaming triggers a surge of adrenaline, helping the target of an attack to enter a full fight-or-flight state.
Julie Gayton
Oxford, UK
I cannot scream, but instead freeze if seriously threatened. In the natural world, there are a variety of responses to threat. Some creatures have an alarm call to alert others of danger, and a shriek if caught – presumably a final attempt to summon help. Others freeze if they have predators who detect their presence by movement (e.g. frogs and spiders, some felines and ground-nesting birds).
So, presumably it depends upon the type of predator and also vegetation type – such as long grass or forest – as to whether screaming or freezing aids survival.
In my case, I once felt great fear when a chair lift in the Alps stopped moving and marooned me suspended over a vertical cliff. The operators thought the last person that day had already come down. As I couldn’t scream, in desperation I tried alpine yodelling. Thankfully, it worked.
To answer this question – or ask a new one – email lastword@newscientist.com.
Questions should be scientific enquiries about everyday phenomena, and both questions and answers should be concise. We reserve the right to edit items for clarity and style. Please include a postal address, daytime telephone number and email address.
Â鶹´«Ã½ retains total editorial control over the published content and reserves all rights to reuse question and answer material that has been submitted by readers in any medium or in any format.
