By Dr. Holly Fearnbach, Marine Mammal Research Director
SR3 collaborated with colleagues from 16 different research groups to publish a new paper titled “Morphology of nares associated with stereo-olfaction in baleen whales” in the prestigious scientific journal Biology Letters. The international research team used morphometric measurements from drone images of free-ranging whales to help understand how baleen whales locate prey patches in their marine habitats. Baleen whales have paired blowholes (nares) that allow for something called stereo-olfaction, where each nares operates independently of the other sending different signals to the brain that are then used to identify the direction of an odor. Fourteen baleen whale species were included in this study and a significant relationship was found between nares-width and whale trophic level (where they feed on the food chain). Baleen whale species with the largest nares-width corresponded with feeding on the lowest trophic level (zooplankton) and were best suited for stereo-olfaction. These findings provide evidence that some baleen whale species, like endangered North Atlantic right whales, may be able to localize odorants such as dimethyl sulfide (DMS), an odorous gas emitted by phytoplankton in response to grazing by zooplankton. However, this is also a conservation concern because biofouling on floating plastic debris also emits DMS, which could lead to incidental plastic ingestion by foraging baleen whales.
Aerial image of an open blowhole of a North Atlantic right whale in Cape Cod Bay, Massachusetts, U.S.A. Image taken using a drone during health research, authorized by permit # 17355 from the U.S. National Marine Fisheries Service. Image by John Durban and Holly Fearnbach.