The study, published in the journal Nature, found that diving mammals have a higher concentration of a protein called myoglobin in their muscles than terrestrial mammals. Myoglobin is a protein that stores oxygen in muscle tissue, and it is essential for aerobic respiration, the process by which cells use oxygen to produce energy.
The researchers found that diving mammals have up to 10 times more myoglobin in their muscles than terrestrial mammals. This allows them to store more oxygen and thus extend their underwater endurance.
The study also found that diving mammals have a higher concentration of mitochondria in their muscles than terrestrial mammals. Mitochondria are the organelles that produce energy in cells, and they require oxygen to function. The higher concentration of mitochondria in diving mammals allows them to use oxygen more efficiently and thus extend their underwater endurance.
The researchers believe that the evolution of these adaptations allowed diving mammals to exploit a new ecological niche and become successful predators in the marine environment.
"The evolution of underwater endurance was a key innovation that allowed diving mammals to colonize the oceans," said study lead author Dr. Jeremy Goldbogen. "Our study provides new insights into how these animals evolved this remarkable ability."
