However, up-to-now scientists have been unable to work out how the whales might use their five-metre long pectoral flippers to help catch their food.
Finally, using aerial observations and photographs, they have been able to record whales off the coast of Alaska using their flippers in a technique they have called 'pectoral herding'.
The flippers are used in three distinct ways:
- To stop prey escaping.
- To move water to guide prey into their mouth.
- By flashing the bright, white underside of the flipper to confuse the fish when there is sunlight on the water.
The technique was observed in humpbacks feeding in one particular area in Alaska. The humpbacks have learnt to time their arrival each year to coincide with the release of young salmon from a hatchery in the area. One theory as to why the technique was observed here is that herring, which are a more common prey for humpbacks, naturally school close together when threatened, and are therefore easier to catch using other techniques. Salmon on the other hand do not school so readily so need some extra effort to get them together, hence the use of the flippers.
WDC policy manager, Nicola Hodgins, described the feeding technique as 'Quite ingenious behaviour, which if successful, as it appears to be, will be passed down to future generations.'
Read the article:
Pectoral herding: an innovative tactic for humpback whale foraging
Madison M. Kosma,Alexander J. Werth,Andrew R. Szabo and Janice M. Straley
Royal Society Open Science