how do alligators breathe underwater
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How old do alligators get?
Crocodiles are reptiles, so they have scaly skin. But amphibians like salamanders don’t have scales. Not only do they sometimes have gills, they can actually get oxygen through their skin. The drawback is that they dry out fast.
They may seem to breathe underwater, but really they can only breathe when their nostrils are in the air. Their snouts are shaped so that they can be almost all underwater, but still breathe.
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A crocodile can dive beneath the water’s surface and hold his breath for extended periods of time. The smaller the croc, the less time he can spend underwater. During a voluntary dive, such as when hunting underwater, the crocodile can remain submerged for 10 to 15 minutes. If a perceived threat prompts the animal to dive involuntarily, the underwater time may be 30 minutes or longer. In dire emergency situations, most crocodiles can stay under for up to two hours. During such an extreme dive, the heart rate may drop drastically to only two or three beats every minute in a desperate bid to conserve oxygen.
CROCODILES can hold their breath underwater for more than an hour. Researchers in Cambridge have now shown that this ability depends on a tiny fragment of the animal’s haemoglobin the protein that carries oxygen from the lungs to the rest of the body.
Crocodiles use a waste product of metabolism – the bicarbonate ions formed when carbon dioxide dissolves in water – as the trigger for haemoglobin to unload the oxygen it carries. The more energy the crocodile’s cells burn up, the more carbon dioxide they produce. So the bicarbonate triggering mechanism ensures that large quantities of oxygen are supplied only to the hard-working tissues that need it the most, thus conserving a submerged crocodile’s limited supplies. This efficient system of oxygen allocation, combined with the reptile’s very slow metabolism, explains how it is able to survive underwater for so long.
In fact, the finding could provide evidence for why these dinosaurs came to dominate the land at a time when the air had much less oxygen than it does today.
All of these experiments showed the same result: The air flowed through the lungs in just one direction.