why do whales bury food
The Short AnswerGray whales and some other baleen species feed by scooping mouthfuls of ocean floor sediment, effectively burying their heads in mud to extract buried prey like amphipods and tube worms. This benthic suction feeding strategy lets them exploit food sources few other whales can reach.
The Deep Dive
Gray whales are the ocean's great bottom feeders, and their feeding strategy is unlike almost any other large whale. Rather than lunging through open water at schools of fish, a gray whale rolls onto its right side and plows its head along the seafloor, scooping enormous quantities of mud, sand, and sediment into its mouth. Once engulfed, the whale presses its massive tongue against its baleen plates, expelling water and fine particles while trapping small benthic organisms like amphipods, tube worms, and ghost shrimp. This behavior, called benthic suction feeding, leaves dramatic sediment plumes visible from the surface and carves distinctive pits into the ocean floor. The whales favor shallow coastal waters and continental shelves where these invertebrates thrive in dense colonies. Scientists have observed that gray whales almost always feed on their right side, a preference that causes noticeable wear on the right side of their baleen over a lifetime. This feeding mode is energetically demanding but provides access to a reliable, calorie-rich food source that pelagic filter feeders like blue whales simply cannot exploit.
Why It Matters
Understanding benthic feeding helps scientists track whale health, migration patterns, and the impacts of climate change on ocean floor ecosystems. When gray whales stir up sediment, they redistribute nutrients and oxygen into seafloor communities, acting as ecosystem engineers. Changes in their feeding behavior can signal shifts in prey availability caused by warming waters or pollution, making them valuable bioindicators of ocean health.
Common Misconceptions
Many people assume all whales hunt by gulping massive volumes of water and filtering krill, but gray whales are specialized bottom feeders with a completely different technique. Another myth is that whales intentionally bury food for later consumption, like squirrels caching nuts. Gray whales are not storing food; they are simply accessing prey that already lives buried in the sediment.
Fun Facts
- A single gray whale can displace over 200 tons of sediment per day while feeding on the ocean floor.
- Gray whales almost always feed on their right side, causing their baleen plates to wear down unevenly over their lifetimes.