By Brett Amy Thelen and Dave Huth
We wrote this because amphibians rock. And, as you will see, they rock hard. After understanding just how awesome and amazing amphibians are, everyone should love amphibians to the max. Everyone should bake amphibians a birthday cake. Everyone should elect amphibians for class president. Everyone should concede that amphibians are the coolest vertebrates to ever stare goggle-eyed at the inscrutable sky above.
1. Amphibian Evolution goes WAAAAAAAAY Back
Amphibians are old. As in, “a scale of oldness so vast and deep it crushes your mind to imagine even a fraction of it.” You know how it’s nearly impossible to comprehend what it means to go back in time A MILLION YEARS? Now try thinking about a million years times three hundred. Amphibians arose directly from the first “tetrapods,” which means “everything on land you know that’s not a bug, including yourself.” Without them first flopping up out of the sea into a completely new and challenging life without gills, nothing else about your dry, leggy existence under the sun could be possible. They’ve survived multiple mass extinction events, including the one that wiped out the dinosaurs. And you’ve probably never even said thank you.
2. Salamanders are (bio)massive.
In ecological terms, biomass is defined as the total mass of living organisms in a given place at a given time. Researchers at the Hubbard Brook Experimental Forest in northern New Hampshire found that the biomass of a single salamander species — the northern redback salamander — was more than twice that of all birds in the forest, even during peak bird-breeding season. A Massachusetts study found that the biomass of vernal pool–breeding amphibians in the 53-acre forest surrounding the pool was greater than all the breeding birds and small mammals in the study area combined. All those amphibians spend a lot of time preying on forest invertebrates and wandering through underground burrows, which in turn affects nutrient cycling, gas exchange, and decomposition rates in the forest floor. Love our forests? Thank a salamander!
3. Amphibian skin is like science fiction alien skin.
The more you learn about amphibian skin, the more it will amaze you. Ever wonder how aquatic newts, who breathe air through lungs like we do, survive harsh winters in ice-covered lakes? How do they come up for air with all that ice overhead? They don’t! Instead, they extract oxygen directly from the water by touching it. With their skin.
Even more amazing: some amphibians can sweat poison –and not just any old poison, but some of the most potent neurotoxins known on earth. From their skin. This feat is not limited to tropical rain forest species. In fact, the humble red eft, whom North Americans have surely seen wandering through the woods on rainy summer days, produces toxins that, upon entering the digestive tracts of certain predators, block signals from the predators’ brains that tell its heart to beat and its lungs to breathe. (Important pro tip: DO NOT EAT red efts!) If you had amphibian skin, you would be an honest-to-goodness superhero.
4. The amphibian life cycle is the closest thing to sorcery you’ll ever see.
Amphibians hatch out of eggs as swimming babies that resemble blubbery grapes with tails (frogs and toads) or tiny adults with neck feathers (salamanders). They live like that for months or years, and then they change into something else entirely. Their body parts completely transform. A tadpole has a mouth and digestive tract completely different in form
and function from that of a frog; in other words, a tadpole’s guts disappear and are replaced by frog guts. Salamanders lose their feathery external gills and replace them with internal lungs. They also grow legs where there were exactly zero legs before. When you were a mammal baby, did you absorb nutrients from your tail until you grew fully functional limbs out of the general region of your belly? We didn’t think so.
5. Wood frogs are living ice cubes.
Wood frogs, spring peepers, and gray tree frogs — all common species in our local forests and wetlands — get through the coldest parts of the winter by freezing solid. Their heartbeats and breathing stop entirely . . . but they’re only mostly dead. They’re just waiting out the cold, their cell walls protected by natural antifreeze that they manufacture for the purpose of making it through the winter. When spring comes, they simply thaw out and hop back to life.
6. Spotted salamanders are living solar panels.
If you stumble upon a vernal pool toward the end of May, you may notice that certain spotted salamander egg masses have a greenish glow to them. That green color comes from algae, which are in a symbiotic relationship with the salamander embryos developing inside each egg. The embryos release waste material, which fertilizes the algae. In turn, the algae photosynthesize, producing oxygen for the embryos to “breathe.” In 2011, scientists made a stunning discovery about the algae-salamander connection: this symbiosis not only takes place in salamander eggs, but also inside salamander cells, and the algae provide the embryonic cells with glucose as well as oxygen. In other words, the algae act as internal power stations, generating fuel for the growing salamanders. If this sounds strange and fantastical to you, well, that’s because it is. Vertebrates have complex immune systems, which typically reject the intrusion of foreign species. In fact, the solar-powered spotted salamander is the only known vertebrate to contain another species inside its cells. The algae aren’t essential to salamander survival, but they help: embryos deprived of algae have lower survival rates and exhibit slower growth than their green cousins.
7. Frogs have built-in musical megaphones.
Anyone who has visited a wetland on a spring evening knows the awesome acoustic power of the wee spring peeper. Adult peepers are only about
an inch long, but they have vocal sacs in their chins that expand with every “peep,” amplifying the intensity of each call. Groups of spring peepers, peeping together in chorus, have been measured at 120 decibels, as loud as a rock concert and louder than a jackhammer!
8. Amphibians regenerate.
If a salamander loses its tail to a predator, the tail will grow back. And not just tails. Also legs, jaws, and internal organs. Also eyeballs. Some salamanders are so good at this that, when threatened by a potential predator, they cut off their own tails by flexing their muscles really hard. Are they magic? No, they are simply awesome.
Brett Amy Thelen is Science Director of the Harris Center for Conservation Education, a land trust & conservation education organization in the Monadnock Region of southwest New Hampshire. In addition, Brett serves on the editorial board of Whole Terrain, Antioch University New England’s nationally acclaimed journal of reflective environmental practice. She spends a lot of time mucking around in vernal pools and moving salamanders off of roads, which is just the way she likes it.
Dave Huth is a professor of visual communication and media arts at Houghton College in western New York state. Dave has built a creative professional practice oriented toward communicating about the natural world. He lives and works with his family and many other critters way out in the woods, which is just the way he likes it.
A similar version of this article previously appeared in the Harris Center for Conservation Education newsletter, “Hearsay.”
©2017 Brett Amy Thelen and Dave Huth