A recent study, published in the journal Science and conducted by Chris McKnight from the University of Exeter and Jessica Kendall-Bar from the University of California, has revealed why seals can remain submerged without drowning for long periods.
According to the research, seals have a unique ability to measure the levels of oxygen in their blood. This discovery sheds new light on the extraordinary adaptation of marine mammals to aquatic life.
An exceptional survival mechanism
Unlike other mammals, which usually depend on carbon dioxide (CO2) levels as an indicator to breathe, seals regulate their dives based on the oxygen available in their blood, ignoring the accumulation of CO2.
Experiments conducted with gray seals confirmed that their ability to remain submerged without drowning is directly related to their oxygen levels, allowing them to optimize their time underwater.
The gray seal is distinguished from the common seal by the straight profile of its head, well-separated nostrils, and fewer spots on the body. They lack external ears and typically have large snouts. Male seals are generally darker than females, with lighter spots and often scars around the neck. Females are silver-gray to brown with dark spots.
Evolutionary keys
This ability to measure oxygen levels in their blood is crucial for the survival of seals and other marine species like walruses.
In addition to their well-known ability to store oxygen and reduce their heart rate, this mechanism provides them with a unique evolutionary advantage, allowing them to dive without unnecessary risks.
Implications and scientific contributions
The discovery not only expands knowledge about marine physiology, but it could also be applied to the study of other animals that engage in prolonged diving, such as certain birds and reptiles. According to McKnight, “understanding how seals perceive and use oxygen in their blood is a key advancement in researching their adaptation to the marine environment.”
This finding highlights how evolution has shaped marine mammals to thrive in their environment, emphasizing the complexity of their physiological adaptations.
Cover photo: Adobe Stock
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