No Behavioral Response of Elephants to Tsunami
By Eric Wikramanayake, Conservation Science Program, World Wildlife Fund, and Centre for Conservation Research, Sri Lanka; Peter Leimgruber, the National Zoo's Conservation and Research Center; and Prithiviraj Fernando, Centre for Conservation Research, Sri Lanka, and Wildlife Trust Alliance
After the Asian tsunami on December 26, 2004, some news articles claimed a "sixth sense" forewarned animals of the approaching wave, allowing them to flee to safety (see National Geographic News). Animals ability to detect infrasound or seismic vibrations could explain such a behavioral phenomenon. Elephants are known to respond to infrasound and ground-borne vibrations (see sources). Yet we found no evidence of flight behavior when comparing movement patterns of two radiocollared elephants before, during, and after the tsunami in Yala National Park on Sri Lankas southeast coast, one of the areas most affected.
The elephants GPS-satellite collars record locations at four-hour intervals. The juvenile male ranges within 6 km of the coast. The adult female ranges along the coast. Based on daily observations, the elephants movements between locations average 1,640 feet (Mean + SD: male, 1,690 feet + 1,654; female, 1,880 + 1,699 feet), with distances between 820 and 2,461 being most frequent (Figure a, above). Their movement patterns approximate those of their associated herds.
At 2:01 a.m. on December 26, the female was close to the seashore. The first tsunami waves reached Sri Lankas coast at around 9 a.m. local time. By 10:01 a.m. the female had moved 581 feet east, closer to the coast (Figure b), suggesting she was by the beach when the tsunami hit. After 10:01 a.m. she moved inland in a counterclockwise arc, returning to the beach by 2 a.m. on December 27. Movement distances ranged from 988 to 2,867 feet (Figure b). Further inland, the male elephant showed even less movement. Between 2 a.m. and 2 a.m., his locations were less than 656 feet. By 6 p.m. he had moved 1,476 feet southwest and another 1,745 feet by 10 p.m. (Figure c).
Our movement data suggest no flight behavior by either elephant prior to or during the tsunamis impact. The female even moved toward the beach, not inland. Like the male, her movements were shorter than the average distances previously observed. In contrast, the females herd had moved more than 6.2 miles in the night after the disturbances associated with her capture and collaring (PF pers. obs.).
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