Newswise — Which would be the most frightening to encounter in an African reserve—a pride of lions, a bus full of tourists, or a herd of cattle? In the case of spotted hyenas, the approach of livestock most often puts them on alert. But it is the human connection—herders bringing their livestock to graze—that is the root of the hyenas’ unease.
A study of the impact humans are having on hyenas appears in the February 2010 issue of the Journal of Mammalogy. "Lethal and nonlethal anthropogenic effects on spotted hyenas in the Masai Mara National Reserve" is based on observations of these animals from 1988 to 2006. Two clans of hyenas in the Kenyan reserve were observed. One experienced frequent human disturbance, whereas the other was relatively undisturbed except for tour vehicles passing by.
Although the lion is the hyena’s only natural predator in the reserve, humans are posing a greater threat. Herders bringing their livestock to graze at the edges of the reserve have chased, speared, snared, and poisoned hyenas to ensure the safety of their cattle and their livelihood. The study shows that hyenas in the “disturbed” clan are now associating the approach of livestock—often accompanied by the sound of cowbells around the cattle’s necks—with danger.
Researchers observed the vigilance displayed by spotted hyenas resting, feeding at kills, and nursing cubs. The effects of lions, tour buses, and livestock were noted. The recorded sounds of cowbells and church bells were played near individual hyenas to test their reaction to sounds associated with human interference.
Hyenas exhibited the greatest vigilance on days when livestock were present within their territory. Those in the disturbed clan showed avoidance of open spaces where livestock most frequently graze and avoided herders by becoming more nocturnal.
Although these hyenas are adapting to higher levels of human interference, the resulting changes in their behavior could affect individual fitness and thus have far-reaching effects on population dynamics.
The full text of this article, "Lethal and nonlethal anthropogenic effects on spotted hyenas in the Masai Mara National Reserve" Journal of Mammalogy, Vol. 91, No. 1, February 2010, is available at http://www2.allenpress.com/pdf/mamm-91-01-154-164.pdf.
About the Journal of MammalogyThe Journal of Mammalogy, the flagship publication of the American Society of Mammalogists, is produced six times per year. A highly respected scientific journal, it details the latest research in the science of mammalogy and was recently named one of the top 100 most influential journals of biology and medicine in the last century by the Special Libraries Association. For more information, visit http://www.mammalogy.org/.
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