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African Elephant Alarm Calls Distinguish between Threats from Humans and Bees

The Samburu pastoralists of Northern Kenya co-exist with African elephants, Loxodonta africana, and compete over resources such as watering holes. Audio playback experiments demonstrate that African elephants produce alarm calls in response to the voices of Samburu tribesmen. When exposed to adult m...

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Autores principales: Soltis, Joseph, King, Lucy E., Douglas-Hamilton, Iain, Vollrath, Fritz, Savage, Anne
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3935886/
https://www.ncbi.nlm.nih.gov/pubmed/24586753
http://dx.doi.org/10.1371/journal.pone.0089403
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author Soltis, Joseph
King, Lucy E.
Douglas-Hamilton, Iain
Vollrath, Fritz
Savage, Anne
author_facet Soltis, Joseph
King, Lucy E.
Douglas-Hamilton, Iain
Vollrath, Fritz
Savage, Anne
author_sort Soltis, Joseph
collection PubMed
description The Samburu pastoralists of Northern Kenya co-exist with African elephants, Loxodonta africana, and compete over resources such as watering holes. Audio playback experiments demonstrate that African elephants produce alarm calls in response to the voices of Samburu tribesmen. When exposed to adult male Samburu voices, listening elephants exhibited vigilance behavior, flight behavior, and produced vocalizations (rumbles, roars and trumpets). Rumble vocalizations were most common and were characterized by increased and more variable fundamental frequencies, and an upward shift in the first [F1] and second [F2] formant locations, compared to control rumbles. When exposed to a sequence of these recorded rumbles, roars and trumpets, listening elephants also exhibited vigilance and flight behavior. The same behavior was observed, in lesser degrees, both when the roars and trumpets were removed, and when the second formants were artificially lowered to levels typical of control rumbles. The “Samburu alarm rumble” is acoustically distinct from the previously described “bee alarm rumble.” The bee alarm rumbles exhibited increased F2, while Samburu alarm rumbles exhibited increased F1 and F2, compared to controls. Moreover, the behavioral reactions to the two threats were different. Elephants exhibited vigilance and flight behavior in response to Samburu and bee stimuli and to both alarm calls, but headshaking behavior only occurred in response to bee sounds and bee alarm calls. In general, increasingly threatening stimuli elicited alarm calls with increases in F (0) and in formant locations, and increasing numbers of these acoustic cues in vocal stimuli elicited increased vigilance and flight behavior in listening elephants. These results show that African elephant alarm calls differentiate between two types of threat and reflect the level of urgency of threats.
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spelling pubmed-39358862014-03-04 African Elephant Alarm Calls Distinguish between Threats from Humans and Bees Soltis, Joseph King, Lucy E. Douglas-Hamilton, Iain Vollrath, Fritz Savage, Anne PLoS One Research Article The Samburu pastoralists of Northern Kenya co-exist with African elephants, Loxodonta africana, and compete over resources such as watering holes. Audio playback experiments demonstrate that African elephants produce alarm calls in response to the voices of Samburu tribesmen. When exposed to adult male Samburu voices, listening elephants exhibited vigilance behavior, flight behavior, and produced vocalizations (rumbles, roars and trumpets). Rumble vocalizations were most common and were characterized by increased and more variable fundamental frequencies, and an upward shift in the first [F1] and second [F2] formant locations, compared to control rumbles. When exposed to a sequence of these recorded rumbles, roars and trumpets, listening elephants also exhibited vigilance and flight behavior. The same behavior was observed, in lesser degrees, both when the roars and trumpets were removed, and when the second formants were artificially lowered to levels typical of control rumbles. The “Samburu alarm rumble” is acoustically distinct from the previously described “bee alarm rumble.” The bee alarm rumbles exhibited increased F2, while Samburu alarm rumbles exhibited increased F1 and F2, compared to controls. Moreover, the behavioral reactions to the two threats were different. Elephants exhibited vigilance and flight behavior in response to Samburu and bee stimuli and to both alarm calls, but headshaking behavior only occurred in response to bee sounds and bee alarm calls. In general, increasingly threatening stimuli elicited alarm calls with increases in F (0) and in formant locations, and increasing numbers of these acoustic cues in vocal stimuli elicited increased vigilance and flight behavior in listening elephants. These results show that African elephant alarm calls differentiate between two types of threat and reflect the level of urgency of threats. Public Library of Science 2014-02-26 /pmc/articles/PMC3935886/ /pubmed/24586753 http://dx.doi.org/10.1371/journal.pone.0089403 Text en © 2014 Soltis et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Soltis, Joseph
King, Lucy E.
Douglas-Hamilton, Iain
Vollrath, Fritz
Savage, Anne
African Elephant Alarm Calls Distinguish between Threats from Humans and Bees
title African Elephant Alarm Calls Distinguish between Threats from Humans and Bees
title_full African Elephant Alarm Calls Distinguish between Threats from Humans and Bees
title_fullStr African Elephant Alarm Calls Distinguish between Threats from Humans and Bees
title_full_unstemmed African Elephant Alarm Calls Distinguish between Threats from Humans and Bees
title_short African Elephant Alarm Calls Distinguish between Threats from Humans and Bees
title_sort african elephant alarm calls distinguish between threats from humans and bees
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3935886/
https://www.ncbi.nlm.nih.gov/pubmed/24586753
http://dx.doi.org/10.1371/journal.pone.0089403
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