Researchers Robert Pitman and John Durban from NOAA's Southwest Fisheries Science Center in La Jolla, Calif., observed killer whales hunting in ice floes, off the western Antarctic Peninsula during January of 2009. While documenting the whales' behavior of deliberately creating waves to wash seals off ice floes, the researchers noticed Weddell seals as their primary target, despite the availability of other prey species, particularly the more abundant crabeater seals.
"These killer whales would identify and then attack Weddell seals almost exclusively, even though they made up only about 15 percent of the available seal population," said Pitman.
Killer whales creating waves to wash seals off ice floes in Antarctica had previously been observed only a handful of times. The whales, sometimes as many as seven abreast, charge the ice floe creating a wave that either washes the seal off the ice or breaks the ice into smaller pieces and more vulnerable to another attack. A previous study involving the authors suggested that this very distinctive killer whale population, which they refer to as "pack ice killer whales," is a separate species.
Once the seal was washed off the ice, the killer whales worked as a group to keep it away from hauling onto the safety of another ice floe. The whales seemed to try and confuse the seal by causing turbulence in the water with their flukes and blowing bubbles under the water through their blowholes.
Away from the ice, the whales attempt to tire and eventually drown the animal by pulling it under water by its hind flippers. Eventually the seal succumbs to exhaustion and is usually divided up among the pod members underwater. In most cases, little of the seal's remains float to the surface, but in one instance the carcass rose to the surface and appeared to have been methodically skinned and dismembered before being eaten.
The research conducted for this paper and on killer whale cooperative hunting methods will be the subject of an upcoming documentary by the British Broadcasting Corporation entitled, Frozen Planet.
NOAA's mission is to understand and predict changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources. Visit us at http://www.noaa.gov or on Facebook at http://www.facebook.com/usnoaagov.
Jim Milbury | EurekAlert!
Global threat to primates concerns us all
19.01.2017 | Deutsches Primatenzentrum GmbH - Leibniz-Institut für Primatenforschung
Reducing household waste with less energy
18.01.2017 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH
A Swedish-German team of researchers has cleared up a key process for the artificial production of silk. With the help of the intense X-rays from DESY's...
For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.
According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
24.01.2017 | Physics and Astronomy
24.01.2017 | Life Sciences
24.01.2017 | Health and Medicine