Shari Riff, age 12, of Akron, Ohio,
How does salamander absorb oxygen?
Salamanders are shy little creatures, scurrying out of sight and hiding under shady rocks away from the sunshine. True, they look somewhat like small dragons, but you would never take them to be daring fellows. Yet their remote ancestors were bolder than the boldest dragon. More than 300 million years ago, they left the seas, which had been their hone since life on earth began, to try life on the dry land. They were the first four‑footed creatures to succeed in this daring adventure,
In North America, we have more varieties of salamander than in all the rest of the world, There are more than 125 of them, including newts and mud puppies, hellbenders and the amazing axolotl. Similar animals tend to use the same method for taking oxygen into the blood stream. All the fishes use gills, all the birds use lungs, as do the mammals. But in this matter, the salamanders tend to be individualists. For some absorb oxygen by one method, and some by others,
Salamanders, of course, are amphibians, distantly related to the ,frogs and toads. As the word amphibian suggests, they should spend part of their lives in the water and part on land. In this too they are individualists. The salamander, if ever, leaves the water. The pretty little red‑backed salamander may never go near the water and if dunked he is sure to drown. As infants, however, all salamanders are tadpoles fitted with gills for taking oxygen from the water.
Some land‑dwelling salamanders pass through this fishy stage while still encased in the moist egg. They lose their tiny gills before hatching. Most amphibians develop air‑breathing lungs to replace their fishy gills. But some salamanders never develop lungs, The hellbender loses his gills, but keeps the gill slits.
The tiger salamander and the strange axolotl of Mexico may keep their fishy gills and spend their entire lives in the water. But when forced to live on land, these creatures may develop lungs.
No salamander depends upon lungs or gills for his oxygen supply, for he can absorb oxygen through his skin. He may even absorb oxygen through the lining of his mouth and throat. You can study this marvelous skin under a microscope which magnifies only 30 times. There you see red blood cells pulsing through tiny vessels near the surface. These cells can absorb dissolved oxygen in the moisture on the surface of the skin.
The salamander is damp and clammy to the touch. He is covered with slimy mucus which oozes out from tiny glands in his skin. In dry air, his skin shrivels and loses its marvelous qualities. He must stay in constant damp air which is why we never find the wonderful little fellow in the sunny desert.