Researchers have captured the acrobatics of gray whales as they feed.
New insight into their movements observed them doing headstands and using “bubble blasts” to catch food.
Oregon State University’s Marine Mammal Institute captured drone footage of the whales foraging in waters off the state’s coast.
The whales’ movements, including forward and side-swimming, change as the whales grow, said Clara Bird, a researcher in the Marine Mammal Institute’s Geospatial Ecology of Marine Megafauna Laboratory.
Using drone footage captured over seven years, Bird quantified the gray whales’ behavior and their individual size and body condition. She found that the probability of whales using these behaviors changes with age.
Younger, smaller whales are more apt to use forward swimming while foraging. Older, larger whales are more likely to headstand, a head-down position in which the whale pushes its mouth into the ocean floor. The probability of whales using these behaviors changes with age.
Clara Bird said: “Our findings suggest that this headstanding behavior requires strength and coordination. For example, we often see whales sculling much like synchronized swimmers do while they are head standing.
“It is likely this behavior is learned by the whales as they mature. We have footage of whale calves trying to copy this behavior, but they’re not able to do it successfully.”
The findings were just published in two new papers authored by Bird and co-authored by Associate Professor Leigh Torres, who leads the GEMM Lab at Hatfield Marine Science Center in Newport.
The researchers also investigated why the gray whales perform “bubble blasts” – a single big exhale while they’re underwater that produces a large circle pattern at the surface.
“While it was thought that bubble blasts helped gray whales aggregate or capture prey, our study shows that bubble blasts are a behavioral adaptation used by the whales to regulate their buoyancy while feeding in very shallow water,” Leigh Torres explained.
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