A pair of devious white-bellied sea eagles have been captured on video for the first time repeatedly dropping a large bat into the ocean in what researchers are calling a “novel predation strategy”.
Researchers were observing the large birds of prey on Tioman Island off the coast of Peninsular Malaysia when they came across the previously undocumented scene of seeming torture. A single sea eagle (Haliaeetus leucogaster) is spotted snatching a flying fox (Pteropus hypomelanus) directly from its roost tree near the beach – not abnormal behavior at this known observational study site.
“Although the catch event was outside of our line of sight, we heard a cacophony of vocalizations (probably from the flying fox colony, and later observed the sea-eagle flying out to sea clutching a struggling flying fox in its talons. Once the sea-eagle was about 100 meters [330 feet] out from the shore, it dropped the flying fox into the sea while another sea-eagle flew in circles a short distance away,” write the authors in the Journal of Bat Research and Conservation.
The dramatic scene didn’t end there. Rather than drowning, the flying fox was able to use its forearms to swim to the surface and make its way toward the shore in what turns out to be a previously unrecorded method of swimming. The eagle duo flew back to land, perched themselves in a tree, and were “clearly observing the flying fox as it swam.” After 20 minutes, one of the eagles dashed out from its perch and snatched the fox, flew it back to sea, and again dropped it into the water.
Even then, the flying – er, swimming – fox didn’t give up. The large bat with its distinct foxlike appearance swam back to shore, slowly and laboriously crawling up the beach.
“At this point, we were forced to cut our observations short as we had to move to another site, and left our observation spot near the beach. It was thus unclear whether the sea-eagles repeated this treatment, and if so, how many times further,” write the authors.
Residents of the island confirmed that this type of behavior happens quite often at this location despite it never having been recorded by scientists. The researchers hypothesize that the hunting strategy may be a way for white-bellied sea eagles to use the ocean to tire out or drown large prey with the strength or ability to fight back.
Flying foxes are found in tropical areas, from Madagascar to Asia to Australia. The animal in the video, known as the small flying fox or island flying fox, is considered a species of least concern by the International Union for Conservation of Nature. However, their numbers are decreasing and they are protected on Tioman Island.