{"id":132449,"date":"2016-09-06T11:37:04","date_gmt":"2016-09-06T09:37:04","guid":{"rendered":"http:\/\/germistoncitynews.co.za\/132449\/researchers-are-listening-to-addos-elephants\/"},"modified":"2016-09-06T11:37:04","modified_gmt":"2016-09-06T09:37:04","slug":"researchers-are-listening-to-addos-elephants","status":"publish","type":"post","link":"https:\/\/develop.citizen.co.za\/germiston-city-news\/lifestyle-news\/2016\/09\/06\/researchers-are-listening-to-addos-elephants\/","title":{"rendered":"Researchers are listening to Addo\u2019s elephants"},"content":{"rendered":"
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The best-known call might be the trumpet, but the most common\u00a0and important call is the low-frequency rumble.<\/div>\n
These rumbles are produced via the vibration of a passive vocal fold when it\u00a0is stimulated by\u00a0airflow from the lungs, similar to human speech. Since elephants have massive vocal folds,\u00a0reaching about 10\u00a0to\u00a014cm\u00a0in adults, these passive vibrations produce infrasonic\u00a0frequencies, which are below the range of human hearing. However, these sounds also\u00a0contain audible components that can be perceived by humans when in close proximity to\u00a0elephants.<\/div>\n
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A research group from the University of Vienna led by Dr. Angela Stoeger and Mag. Anton\u00a0Baotic,\u00a0has been studying the communication of the elephants in the Addo Elephant\u00a0National Park since 2011. They are interested in various aspects of this vocal behavior,\u00a0including vocal dialects and individual differences in vocalizations,\u00a0especially since elephants\u00a0seem to know exactly\u00a0who\u00a0is calling.<\/div>\n
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As\u00a0elephants make extensive use of their powerful infrasonic calls for long distance\u00a0communication, they are a perfect model species for acoustic observation because it is\u00a0possible to detect them even if they are out of sight. As such, the Vienna\u00a0research team is\u00a0exploring the use of elephant vocal signals to monitor their movements.<\/div>\n
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Some of their first published results have showed that it is possible to estimate age groups\u00a0of African elephants based on acoustic parameters extracted from the low frequency\u00a0rumbles. The rumbles of calves are higher in pitch than from juvenile and\u00a0adult individuals\u00a0and can be clearly discriminated.<\/div>\n
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Such findings can have important implications for the conservation of this iconic species. The\u00a0new insights about acoustic age classification may help to provide information on herd\u00a0demographics, distribution and densities.<\/div>\n
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However, researchers are also testing whether it\u00a0might be possible to use vocalizations to regulate elephants<\/div>\n
impact on the surrounding\u00a0biodiversity, by manipulating how these large mammals use the space.<\/div>\n
The idea is to play certain calls (for example alarm calls) back to them,\u00a0to induce spatial and\u00a0temporal variation in the intensity with which elephants use landscapes.<\/div>\n
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Before this can be\u00a0tested, the researchers need to understand the meaning of particular vocalizations to them.<\/div>\n
In order to do this, they are conducting playback experiments.\u00a0This involves two research vehicles driving around Addo, one of which is equipped with\u00a0a\u00a0custom-built subwoofer that can produce infrasound. This vehicle is hidden behind trees\u00a0outside of the view of elephants, while researchers in the other car document the\u00a0behavioral response to the infrasound.<\/div>\n
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These experiments have demonstrated that elephants respond differently to human- and\u00a0bee-induced alarm rumbles. The\u00a0ir\u00a0responses are population specific, as elephants adapt to\u00a0threats that are of particular importance for them. For instance, a female group\u00a0with calves\u00a0will probably react differently to particular alarm signals or other kinds of\u00a0threat signals than\u00a0a group of young males, or a musth-male (a male displaying rutting behavior).<\/div>\n
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It will\u00a0therefore be crucial to investigate differences in behavioral responses of various individuals\u00a0and groups of elephants.\u00a0The Vienna research team is optimistic that the idea of an acoustic monitoring and deterrent<\/div>\n<\/div>\n<\/div>\n
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system is feasible and can be implemented in the future, but years of research will still be\u00a0necessary in order to develop the fundamental knowledge about elephant vocal behavior\u00a0crucial to this intended system.<\/div>\n<\/div>\n<\/div>\n<\/p>
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