The salt concentration in seawater is about 35 grams per liter of seawater. Penguins spend a great deal of the day swimming in the ocean or living on shores. As an accompaniment to daily life, they drink seawater. But how do they neutralize these effects to them, concerning drinking such high quantities of salt?
Penguins have a special superpower-an inner mechanism to solve this problem. They have supraorbital glands, located just above their eyes. Such glands form an important part of the salt-filtering system of a penguin. Unlike most other land animals, which require fresh water sources, penguins can drink seawater and cannot be dehydrated or poisoned by salt. Now, let's see their mechanism in action:
As the penguins drink sea water, supraorbital glands extract excess salt in their blood. These glands perform the function of a desalination plant; they separate sodium chloride from their blood and expel the salt in very high concentration.
This filtered salt is then excreted through the nostrils of the penguin. Once the salt has accumulated, it just snorts or shakes its head to remove it, and the salty particles that have built upon its beak fall off. When you catch a glimpse of an ostracized penguin sneezing away, well, it's not just clearing out pathogens in its airways-it's actually spitting out the excess salt!
This fantastic adaptation is necessary because penguins find almost no fresh water in their habitats. Most penguin species, just like the Emperor Penguin, spend much of their time in the sea; they swim or rest on ice floes. Such environments contain very little fresh water at all. Hence, the ability to drink seawater gives them an essential edge for survival.
Supraorbital glands are only one category of salt glands found in birds such as albatrosses and seagulls, but perhaps the most famous association of this type of evolutionary adaptation is with penguins.
This inherent desalination system was meant to make life even in the most hostile oceanic conditions possible for the penguins as they were adapted to living off their surroundings. The salt gland is most active during swimming and hunting because more saltwater is absorbed by the body at such moments. Pelauctions to excess sodium chloride filtered, penguins avoid any harmful salt accumulation in their bodies, an occurrence that might bring about dehydration or other health problems.
Such adaptation has allowed penguins to live successfully in ocean waters having no fresh water, as in Antarctica and the sub-Antarctic islands of the Southern Hemisphere. Their use of seawater as a source of drinkable water has proven to be one of the best testimonials to their indurateness and resilience.
So next time you see a penguin, whether in the wild or in the zoo. Remember that these unbelievably interesting birds have a special, seemingly superpower-one that lets them live a life most other animals could never survive.
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