The paper referred to in the below article can be found at freely online at:
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Elephants can tell when a storm is approaching, even if it’s 150 miles away.
Scientists hope one day to use this ability to save them from being killed by the thousands by poachers.
Researchers analyzed data from GPS tracking devices placed on elephants in 14 different herds in the Nambia region of Africa and plotted the elephants’ movements for seven years. The region has a distinct rainy season and conditions are usually hot and dry with little precipitation.
The researchers found that elephants can “sense” thunderstorms—often hundreds of miles from their current location—and seem to predict approaching rain several days before it occurs.
“The onset of the rainy season there is very abrupt and lasts just a few weeks, and the rest of the time, there is little or no rain at all,” explains Oliver Frauenfeld, assistant professor in the geography department at Texas A&M University.
“With the GPS device attached to them, we learned that the elephants can detect thunderstorms at great distances. We don’t know if they can actually hear the thunder or if they are detecting other low-frequency sounds generated by the storms that humans can’t hear. But there is no doubt they know what direction the rain is.”
Getting Elephants to Safety
Frauenfeld says the information could have conservation implications for helping elephants survive the rampant poaching trade in Africa by allowing wildlife officials to better predict the location and movement of elephant herds.
A recent study by National Geographic estimates that at least 100,000 elephants were killed during a three-year period from 2010-2012, and Central Africa has lost 64 percent of the elephant population in the last decade. Some localized populations could be wiped out entirely within the next 10 years, the study says.
“While the environmental trigger that causes their movements remains uncertain, rain-system generated infrasound, which can travel great distances and be detected by elephants, is a possible trigger for changes in their migration patterns,” Frauenfeld adds.
“Our study suggests that the elephants are responding to a common environmental signal. The change in their movements occurs well before—from days to weeks—of any rain in the elephants’ current location.”
Coauthors from the University of Virginia, Australia’s University of New South Wales and the University of Utah contributed to the study, which appears in PLOS ONE.
Response of African Elephants (Loxodonta africana) to Seasonal Changes in Rainfall
Robert E. Davis,
Oliver W. Frauenfeld,
October 09, 2014
The factors that trigger sudden, seasonal movements of elephants are uncertain. We hypothesized that savannah elephant movements at the end of the dry season may be a response to their detection of distant thunderstorms. Nine elephants carrying Global Positioning System (GPS) receivers were tracked over seven years in the extremely dry and rugged region of northwestern Namibia. The transition date from dry to wet season conditions was determined annually from surface- and satellite-derived rainfall. The distance, location, and timing of rain events relative to the elephants were determined using the Tropical Rainfall Measurement Mission (TRMM) satellite precipitation observations. Behavioral Change Point Analysis (BCPA) was applied to four of these seven years demonstrating a response in movement of these elephants to intra- and inter-seasonal occurrences of rainfall. Statistically significant changes in movement were found prior to or near the time of onset of the wet season and before the occurrence of wet episodes within the dry season, although the characteristics of the movement changes are not consistent between elephants and years. Elephants in overlapping ranges, but following separate tracks, exhibited statistically valid non-random near-simultaneous changes in movements when rainfall was occurring more than 100 km from their location. While the environmental trigger that causes these excursions remains uncertain, rain-system generated infrasound, which can travel such distances and be detected by elephants, is a possible trigger for such changes in movement.