Scientists Found That Larger Gray Whales Exhale Bubble Blasts To Help Them Stay Underwater
Over the course of seven years, scientists have used drones to record gray whales off Oregon’s central coast.
The extensive video footage has offered new insight into the various techniques these marine mammals use to find food.
Apparently, gray whales employ different swimming strategies to forage for food, depending on their sizes and ages. For example, to help them stay underwater, larger whales are more likely to exhale “bubble blasts.”
“Before this study, we thought that any whale used any of those behaviors,” said Clara Bird, the lead author of the study and a researcher at Oregon State University’s Marine Mammal Institute. “No one really thought that there was a pattern in who used which behavior.”
According to Bird, the depth of the water also played a role in the techniques the whales used to eat their prey.
The information could be helpful for future conservation work because it reveals which habitats are most important to preserve.
Part of the gray whale population is listed as endangered under the Endangered Species Act. The entire species was once in danger of extinction due to commercial hunting.
Gray whales used to be common across the Northern Hemisphere, but now they are only regularly seen in the North Pacific.
According to a 2020 report from the National Oceanic and Atmospheric Administration, it was estimated that just under 27,000 gray whales were in the area as of 2016. The whales eat amphipod crustaceans like tiny shrimp and worms.
FPLV – stock.adobe.com – illustrative purposes only, not the actual whale
They consume their prey by sucking up water and sediment from the seafloor. Then, they use their baleens to filter the food.
Usually, gray whales are observed alone or in small groups, but large groups may gather at feeding or breeding grounds.
Bird and colleagues conducted their research off Newport on sailing trips over seven years. They used drones to track and record individual whales.
From 2016 to 2022, the team tracked 78 gray whales. They observed that younger, smaller whales tended to swim sideways or facing forward. The whales also opened and closed their mouths to find and consume food.
Meanwhile, older, bigger whales often dive and stay in place with their head down underwater. Scientists called it the “headstand technique.” As a whale got larger, the chances of such headstands being performed grew more likely.
At the same time, the probability of the forward-swimming strategy decreased. Water depth and habitat type—sandy, rocky, or coral reef—also influenced the whales’ approaches.
The switch between techniques is attributed to the maturity of a whale’s muscles, as well as its levels of coordination and strength.
When older, bigger whales search for food, they typically release air from their blowholes to help them stay underwater.
The “bubble blasts” help whales sink since the bigger they are, the more prone to floating they are. On average, a bubble blast appeared about 27 seconds after a whale dove for food. Most of them occurred while the whales were doing headstands.
There is still so much that is unknown about whales and their behavior. The drone footage helps provide details that researchers would otherwise miss.
The study was published in Ecology and Evolution.
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