Researchers have published two studies into how dolphins manage to have different lifestyle and diving habits, amongst different populations of the same species.
The research was prompted by the fact that the difference in diving ability can be in excess of 1000m/3300ft amongst dolphins of the same species.
According to Dr. Andreas Fahlman from the Fundación Oceanográfic in Valencia, Spain, the team wanted to answer the question:
“How can a single species have such extremely different life styles?”
After extensive research, the first study found that surprisingly, there is no difference in the lung mechanics or function between deep- and shallow-diving dolphin populations. this finding lead to the second study, which tried to uncover which mechanisms the deep-diving dolphins use to mange gas in their bodies.
The second study provided some very interesting results and has opened the door to much more research into how mammals deal with various gases when diving deep. Researchers concluded that between dives, the deep-diving dolphin population must keep its heart rate elevated to properly oxygenate their tissues.
Once a deep dive has commenced, the dolphin would then direct blood flow through a collapsed area of the lung. This would lead to minimal exchange of oxygen and carbon dioxide during the dive but would also severely restrict the absorption of nitrogen. This helps protect the dolphins from DCS and other nitrogen problems.
The research leads to other questions, about how environmental stressors and human action can cause changes to mammals’ and dolphins’ deep-diving adaptations, and how we can minimize our impact on them.
For more info, check out the article in Frontiers in Physiology.