You may be familiar with the spectacular lunge feeding strategies of humpback whales, or the amazingly advanced attacks orca pods coordinate. The range of feeding behaviors across cetacean species is fascinating, but one such strategy you might not be familiar with is that of the grey whale.
Gray whales are filter feeders, sifting their food through baleen plates. But unlike any other species of whale, grey whales strain the sediment of the sea floor for food. They swim along, sucking up mouthfuls of sediment and spitting out everything but their prey. What are they looking for? Tiny amphipods, shrimp-like animals that live inside that sediment. Along with the amphipods, grey whales will also consume cumaceans, isopods and mysids among other tiny animals scraped up from the floor.
But to get at these small sea creatures, grey whales put on a rather interesting feeding show.
Arkive describes the behavior:
Individuals roll onto their sides after diving to the bottom and take large amounts of sediment into their mouth. As the whale rises to the surface, it strains the contents of the mouth through the baleen, leaving a trail of mud and sand behind it. The invertebrate prey consisting of bottom-dwelling crustaceans, worms and molluscs is isolated in this way and swallowed. A number of seabirds are attracted to feeding gray whales, and take advantage of invertebrates that escape the filtering process.
Here's an example of what this feeding strategy looks like when viewed from above. This grey whale was filmed feeding along the rocky shoreline near Yaquina Head Lighthouse in Newport, Oregon.
Next time you see grey whales rolling next to rocks or kicking up mud in a shallow cove, you'll know they’re probably just taking their next mouthful of food.