Tuesday, January 19, 2021

Do Marine Mammals get “the Bends?”


Any well trained SCUBA diver ascending from the depths of a dive is taught about the hazards of decompression sickness (DCS), commonly referred to as “the bends.” As the SCUBA diver swims upwards in the water column, the pressure surrounding them decreases, such that gases (like nitrogen) that were absorbed by the body during a dive, come out of solution and, if their ascent is too rapid, can cause bubbles to form in the body. DCS can manifest a variety of symptoms, and the effects may vary from joint pain and skin rashes to paralysis and sometimes even death.

But how do marine mammals, whose very survival depends on constant diving, manage to avoid DCS? And are they actually avoiding it or is something else occuring?

A recent study published by the biological sciences arm of the Royal Society  suggests diving mammals vary their physiological responses according to multiple stressors, such as gas-bubble incidence.

Until recently the dogma was that marine mammals have anatomical and physiological and behavioral adaptations to make the bends not a problem,” said WHOI Marine Mammal Center Director Michael Moore. “There is no evidence that marine mammals get the bends routinely, but a look at the most recent studies suggest that they are actively avoiding rather than simply not having issues with decompression.”

Read more about it at Science Daily.

Do Marine Mammals get "the Bends?" 1

Do Marine Mammals get "the Bends?" 5
Francesca Koehttps://www.deeperblue.com/
An active ocean advocate, VP of U.S. Freediving, a multi-agency dive instructor, PFI Safety Supervisor and AIDA judge, Francesca also serves as the Editor-At-Large here at DeeperBlue.com. You can usually find Francesca diving in the kelp, hanging out at the Farallones with sharky friends, or trying to improve upon her own PB's.


  1. How do marine mammals manage to not get the bends? I always assumed they too dove with compressed air scuba tanks attached to their backs….

  2. Dr. Paul’s got it right. While it is still possible to get some gas anomalies without compressed air, it is exceptionally rare and usually involves other issues being present. For diving marine mammals, they are diving with a set amount of air in their lungs, a volume that no matter how fast or slow they ascend will never expand beyond its original size at the surface, which means that since they have no way of “loading” their bodies with excess amounts of gases at depth, the partial pressures of the gases in the bloodstream will be negligibly similar along depth gradients. 

    The real topic of interest is how marine mammals are able to avoid things like shallow and deep water blackouts so effectively, along with the physiological aspects related to such a skill. 


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