Surviving in the cold air temperatures of the Arctic is no easy feat for seals. Beyond the thick layers of blubber that provide insulation, Arctic seals have adapted their nasal passages to better retain moisture and heat. A study published December 14 in the Biophysical Journal found that Arctic seals have more convoluted nasal passages than seals in milder environments.
When breathing in cold air, animals lose moisture and heat, which can be harmful to lung function and make them more susceptible to respiratory viruses. To combat this, most birds and mammals have specialized bones called maxilloturbinates in their nasal cavities. These bony shelves help to warm and humidify inhaled air and reduce the loss of heat and moisture when exhaling.
According to Signe Kjelstrup, a study co-author and physical chemist at the Norwegian University of Science and Technology, the complex nasal structure of Arctic seals helps them lose less heat through nasal heat exchange compared to seals in other climates, giving them an evolutionary advantage.
Arctic seals are able to retain 94 percent of the moisture in the air when they breathe in and out, allowing them to efficiently conserve heat and energy in their harsh environment. The unique maxilloturbinate structure of their noses helps them achieve this remarkable feat.
The differences in maxilloturbinate structures are also evident when comparing other species. Reindeer, for example, have similar nasal structures that enable efficient heat exchange, but they are only found in colder climates. While reindeer are not found in warmer climates, seals inhabit a wide range of environments, making them ideal subjects for the study.
In their study, researchers used computer tomography to create 3D models of the nasal cavities of two seal species—the Arctic bearded seal and the Mediterranean monk seal. By comparing how well each species warmed and moistened air when they inhaled, as well as their ability to reduce the loss of heat and moisture when they exhaled, the researchers were able to gain valuable insights into the unique adaptations of Arctic seals.
They tested the models of both species’ noses under Arctic conditions of -22°F and at about 50°F. These findings shed light on the incredible adaptability of Arctic seals and their ability to thrive in challenging environments. To learn more about the fascinating study, read the full article here.Â
