Behavior

Headstands, upside-down swimming, jaw snapping, benthic digs, bubble blasts. These are some of the cool, unique feeding behaviors that gray whales use to capture food along the Oregon coastline.

Unlike most other large whales, Oregon gray whales that belong to the Pacific Coast Feeding Group (PCFG) feed very close to shore and in very shallow water, often less than 50 ft (15 m) deep, which is amazing when you think that these whales are about 40 ft (12 m) long!
By flying drones over, and deploying suction-cup accelerometry tags on, Oregon gray whales, and then carefully analyzing these data, we documented these interesting feeding behaviors and found some interesting patterns.
  1. As these PCFG gray whales grow and age, they switch their primary feeding tactic from forward swimming (either on their side or upside-down) to headstanding. We think it takes a lot of strength and coordination to headstand, so whales may need several years to learn how to headstand.
  2. When headstanding, longer gray whales use “bubble blasts”, which are an underwater exhalation of air through their blowhole, more often. These bubble blasts allow the whale to feed for a longer period of time because it reduces their buoyancy while feeding in shallow water. Just like when we snorkel or scuba dive, if we release air from our lungs, we don’t fight buoyancy forces as much, so it’s easier to stay underwater.
  3. The three primary feeding behaviors gray whales in Oregon use are headstands, benthic digs, and side swims. On average, these PCFG gray whales spend most of their time searching and foraging, and only ~20% travelling.
  4. During daytime, Oregon gray whales mainly roll to their right to feed, but at night they perform more left-sided rolls and feed in shallower water compared to during the day.

Want to read more? Check out these resources:

Bird CN, Pirotta E, New L, Bierlich KC, Donnelly M, Hildebrand L, Fernandez Ajó A, Torres LG (2024) Growing into it: evidence of an ontogenetic shift in grey whale use of foraging tactics. Anim Behav 214:121-135
https://doi.org/10.1016/j.anbehav.2024.06.004. https://www.sciencedirect.com/science/article/pii/S0003347224001556

Bird CN, Pirotta E, New L, Bierlich K, Hildebrand L, Fernandez Ajó A, Torres LG (2024) Bubble blasts! An adaptation for buoyancy regulation in shallow foraging gray whales. Ecology and Evolution 14:e70093
https://doi.org/10.1002/ece3.70093.
https://doi.org/10.1002/ece3.70093

Colson KM, Pirotta E, New L, Cade DE, Calambokidis J, Bierlich KC, Bird CN, Ajó AF, Hildebrand L, Trites AW, Torres LG (2024) Using accelerometry tags to quantify gray whale foraging behavior. Mar Mamm Sci n/a:e13210
https://doi.org/10.1111/mms.13210.
https://onlinelibrary.wiley.com/doi/abs/10.1111/mms.13210

Press release:

https://news.oregonstate.edu/news/drone-footage-provides-new-insight-gray-whales%E2%80%99-acrobatic-feeding-behavior