Marine mammals have a special ability, one that humans can hardly replicate. They can hold their breath for hours inside water appearing on the surface for a brief second to fill up and submerge again. Now scientists say they have finally found the property that allows these mammals to do so.
Marine mammals like whales and seals can remain underwater for hours at a time holding their breath. Scientist say that this is because of myoglobin, an oxygen-storing protein in mammals’ muscles which in the case of these animals has a special “non-stick” property.
It is this special property that allows the mammals to pack huge amounts of oxygen in their muscles without “clogging them up”.
Dr Michael Berenbrink from the Institute of Integrative Biology at the University of Liverpool says,
“At high enough concentrations, [proteins] tend to stick together, so we tried to understand how seals and whales evolved higher and higher concentrations of this protein in their muscles without a loss of function,” he said about the research that was published in Science.
To solve the mystery the team extracted pure myoglobin from a variety of mammals from land based cows, semi aquatic otters to purely aquatic animals like the sperm whale.
The research revealed that the marine animals had a changed chemistry of the myoglobin protein that allowed more oxygen to be stored inside their bodies.
Dr. Berenbrink calls it a chemical trickery where marine mammal myoglobin is positively charged.
“Like the similar poles of a magnet; the proteins repel one another. In this way we think the animals are able to pack really high concentrations of these proteins into their muscles and avoid them sticking together and clogging up the muscles.”
The scientist adds that this finding is of more significance because it helps in revealing the kind of changes that occurred during evolution when marine mammals evolved to land based animals.
It showed, he said, the physiological change that accompanied the land to water transition of mammals.
“It also allows us to estimate the dive times of the ancient ancestors of whales,” Dr Berenbrink explained. “We can look the fossils and predict the dive times they had.”
The research could also help in medicine science, where the same chemistry is applied to create oxygen carrying liquids that would supply oxygen to people’s tissues when blood transfusion is not possible.
Nicholas Pyenson, curator of fossil marine mammals at the Smithsonian Institution in Washington DC, said that the study was an exciting advancement for understanding the evolution of deep-diving.
“The idea that we can estimate maximal dive times for early diverging relatives of today’s marine mammals will have a profound impact on how we think about their ancient ecology and biology,” he said.
Professor Michael Fedak from the University of St Andrews’ Sea Mammal Research Unit said that though myoglobin was just one part of the whole mammal diving puzzle, it was an important part.
He adds that the scientists are also trying to find out how marine mammals are repeatedly able to cut off and re-establish blood supply in their body tissue without any problem which is equivalent to a crash injury.
“But being able to pick up a few [fossilised] bones of an extinct marine mammal and estimate its dive time from that – that’s miraculous.”
At least one part of the puzzle is now vividly clear.