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From: The Arizona Republic (online print edition)
For lungless salamanders there's no waiting to exhale
Nov. 8, 2003
DEAR PET DOCTOR: Is it true that there are salamanders that don't breathe?
DEAR READER: Sure, dead ones.
All living animals need to breathe, but the way some do it - without inhaling and exhaling all the time - may not seem like breathing to you.
Many salamanders don't have lungs or gills. They simply breathe using other parts of their bodies, such as their skin.
Plethodontids (lungless salamanders) are typically very small, generally no larger than a ballpoint pen. They have a very low metabolism, so they don't use much oxygen. Combine those two traits and you have animals that can do away with lungs.
Lungs are really nothing more than internal folds of moist skin designed to enhance the exchange of oxygen and carbon dioxide from red blood cells. High-energy animals such as mammals have very complicated lungs to process this chemical reaction; low-energy animals such as lungless salamanders are able to get by "breathing" through their thin, moist skin.
Not having lungs is not all that big a problem. In fact, there are more kinds of lungless salamanders than any other kinds of salamanders. The plethodontids are widely distributed in the New World; the eastern United States is the hotspot for diversity, with more species than anywhere else in the world.
Salamanders are the most successful vertebrates in some of these ecosystems. One study estimates that the total weight of lungless salamanders living in one square mile of the Allegheny Mountains forest is more than that of all of the other vertebrates in that same area combined.
How can something so small be so important to the ecosystem? Well, due to their small size and low metabolism, plethodontids can feed on insects too tiny for other vertebrates to bother eating. Billions of insects fall into this category, giving salamanders an unlimited food source, one untapped by reptiles, birds or mammals.
Salamanders in turn are eaten by reptiles, birds and mammals, and so on up the food chain.
Lungless salamanders show tremendous diversity. Slimy salamanders are a beautiful shiny black with white polka dots dusting their back like wayward shakes of powdered sugar. Their name gives a clue to their defense - they produce incredibly sticky secretions when handled, secretions that are about 10 times as sticky as rubber cement.
Red salamanders are coral red with pepper spots, probably the most glamorous salamander around. Green salamanders live in crevices on wet mountainsides, tending eggs that hatch into babies without having to go through an aquatic larval stage like most other amphibians. There are hundreds more species out there.
Arizona is one of the few states that has no plethodontids. We have a couple of native tiger salamanders, but these giants have lungs.
Kevin Wright is director of conservation, science and sanctuary at the Phoenix Zoo. Write to him at 455 N. Galvin Parkway, Phoenix, AZ 85008, or DoctorKevin@thephxzoo.com.
Source: http://www.azcentral.com/arizonarepublic/arizonaliving/articles/1108petdoc08.html
For lungless salamanders there's no waiting to exhale
Nov. 8, 2003
DEAR PET DOCTOR: Is it true that there are salamanders that don't breathe?
DEAR READER: Sure, dead ones.
All living animals need to breathe, but the way some do it - without inhaling and exhaling all the time - may not seem like breathing to you.
Many salamanders don't have lungs or gills. They simply breathe using other parts of their bodies, such as their skin.
Plethodontids (lungless salamanders) are typically very small, generally no larger than a ballpoint pen. They have a very low metabolism, so they don't use much oxygen. Combine those two traits and you have animals that can do away with lungs.
Lungs are really nothing more than internal folds of moist skin designed to enhance the exchange of oxygen and carbon dioxide from red blood cells. High-energy animals such as mammals have very complicated lungs to process this chemical reaction; low-energy animals such as lungless salamanders are able to get by "breathing" through their thin, moist skin.
Not having lungs is not all that big a problem. In fact, there are more kinds of lungless salamanders than any other kinds of salamanders. The plethodontids are widely distributed in the New World; the eastern United States is the hotspot for diversity, with more species than anywhere else in the world.
Salamanders are the most successful vertebrates in some of these ecosystems. One study estimates that the total weight of lungless salamanders living in one square mile of the Allegheny Mountains forest is more than that of all of the other vertebrates in that same area combined.
How can something so small be so important to the ecosystem? Well, due to their small size and low metabolism, plethodontids can feed on insects too tiny for other vertebrates to bother eating. Billions of insects fall into this category, giving salamanders an unlimited food source, one untapped by reptiles, birds or mammals.
Salamanders in turn are eaten by reptiles, birds and mammals, and so on up the food chain.
Lungless salamanders show tremendous diversity. Slimy salamanders are a beautiful shiny black with white polka dots dusting their back like wayward shakes of powdered sugar. Their name gives a clue to their defense - they produce incredibly sticky secretions when handled, secretions that are about 10 times as sticky as rubber cement.
Red salamanders are coral red with pepper spots, probably the most glamorous salamander around. Green salamanders live in crevices on wet mountainsides, tending eggs that hatch into babies without having to go through an aquatic larval stage like most other amphibians. There are hundreds more species out there.
Arizona is one of the few states that has no plethodontids. We have a couple of native tiger salamanders, but these giants have lungs.
Kevin Wright is director of conservation, science and sanctuary at the Phoenix Zoo. Write to him at 455 N. Galvin Parkway, Phoenix, AZ 85008, or DoctorKevin@thephxzoo.com.
Source: http://www.azcentral.com/arizonarepublic/arizonaliving/articles/1108petdoc08.html