New publication: Nares modulation in breathing cetaceans reflects respiratory mechanics

Written by Cameron Nemeth

We are pleased to share a new publication in Marine Mammal Science, entitled: Nares modulation in breathing cetaceans reflects respiratory mechanics

Authors: Cameron Nemeth, Joy Reidenberg, Lars Bejder and Andreas Fahlman

A humpback whale breathing at the surface on a brisk morning in Southeast Alaska. Credit: Alaska Whale Foundation Field Team (NOAA permit #19703)

Overview:

Cetaceans (dolphins, whales, and porpoises) possess a specialized respiratory system designed for highly efficient gas exchange during brief surfacing intervals. Knowing this, when I saw the video below, I was confused as to why the blowholes of this blue whale seemed to be very constricted during the exhalation phase of the breath. I mean, why not open the blowhole as wide as possible to quickly exchange the most air?

Close up video of a blue whale blowhole during a surfacing. Video was taken from a drone equipped with a zoom lens and cropped in. Credit: Chris Crass (AquaTerra)

This curiosity led me to search all over the internet to find similar examples, and sure enough, I did. I sourced ten, high-quality videos of six different cetacean species, and obtained permission from all videographers to use their drone footage for my analyses. The goal of this study was to examine how blowhole area changes throughout a breath and to propose hypotheses regarding the function of this modulation, grounded in respiratory mechanics of cetaceans and other mammals.

CATS tag footage of a humpback whale blowhole during a surfacing. Note the rapid widening of the blowholes immediately following the exhalation spout. Credit: Marine Mammal Research Program (NOAA permit #27548)

We observed that the blowholes were very constricted at the beginning of the exhalation, slowly grew in size throughout the exhalation, and then quickly expanded at the onset of inhalation. The blowholes remained maximally expanded for the majority of the inhalation. This pattern was relatively consistent for both dolphins and whales.

A blue whale’s blowhole during different phases of a breath: (A) beginning of exhalation, (B) end of exhalation, and (C) mid-inhalation. Screenshots were taken from a drone equipped with a zoom lens and cropped in. Credit: Chris Crass (AquaTerra)

In most surfacings, the blowhole area roughly doubled from the start of inhalation to its maximum size. In one striking case, a blue whale about to make a deep dive expanded its blowhole by 500% between exhalation and inhalation. This dramatic increase likely helps the whale load up on oxygen before staying underwater for longer, although more data are needed to fully support this idea.

Though one might expect a whale’s blowhole to be maximally expanded throughout an entire breath to maximize gas exchange, we propose several hypotheses for the narrowed blowhole opening observed during exhalation. First, a narrowed opening may increase pressure in the whale’s lower airways, helping to keep them open and allowing more complete emptying of the lungs. This mirrors a breathing technique called “pursed-lip breathing”, that is often prescribed for people with chronic obstructive pulmonary disease (COPD). As whales must contract muscles to open their blowholes, we also hypothesize that a narrower opening during exhalation could reduce the energetic cost of breathing. Lastly, whales sometimes accidentally take in water into their blowholes, and narrowing the opening may help flush that water from the respiratory tract more rapidly, similar to putting your thumb over a hose to increase the speed of the water.

A large blowhole opening during inhalation likely reduces airflow resistance, making it easier for the respiratory muscles to draw air into the lungs. A larger opening also allows more oxygen to be taken up with each breath, or enables whales to shorten the duration of a surfacing. Finally, a wide blowhole during inhalation permits air to move at a slower speed, increasing pressure within the airway and helping prevent collapse — a problem that many horses experience due to their exceptionally high airflow rates.

As a student who recently completed my undergraduate degree and had no data of my own, I hope this publication also encourages early-career researchers to think creatively about how they acquire and use data. There is a vast amount of content available online, and while it can take time to identify high-quality material, I have found that many videographers and tour operators are enthusiastic about contributing to science. These collaborations offer unique opportunities to advance our understanding of species that are often cryptic and difficult to study, frequently requiring intensive and costly field efforts.

With that in mind, I would like to conclude by sincerely thanking the videographers and tour operators who contributed to this study. We are extremely grateful to Domenic Biagini (@DolphinDroneDom), Chris Crass (AquaTerra), Maxi Jones (@MaxiJonas), Mark Girardeau (@markgirardeau), and Gone Whale Watching San Diego for generously providing the drone footage used in our analyses.

Full citation: Nemeth, C., Reidenberg, J. S., Bejder, L., & Fahlman, A. (2026). Nares Modulation in Breathing Cetaceans Reflects Respiratory Mechanics. Marine Mammal Science, 42(1), e70115. https://doi.org/10.1111/mms.70115

doi: https://doi.org/10.1111/mms.70115