Inside the Outdoors: Amphibious, amphibian, and related fine points
Most of us would understand the term "amphibious" to mean by-water or over-water. The invasion of Nazi-held Europe and the South Pacific islands occupied by the Japanese during World War II exemplifies this meaning of the term. Barge-like boats optimistically called "landing craft" carried soldiers from ships to shore in carrying out these amphibious invasions.
Some who know automotive trivia may have heard of the Amphicar, a highway vehicle marketed as "A Car That Swims," which could travel over water if the driver was judicious enough not to take on large waves or strong winds. The "am" in Amphicar stood for "amphibious." The car was marketed from 1961 to 1968, built in West Germany to be sold here.
Amphibian in the world of Nature has a similarly aquatic meaning. It describes an animal that begins life as a fish-like creature that obtains oxygen under water by means of gills, and morphs into a creature with lungs that breathes air in the atmosphere as we do. But there the similarities between some amphibians diverge, like travelers who reach a fork in the road leading to very different destinations. The amphibians we're most familiar with have some striking similarities, but some real differences, too. Some that even lead to questionable prejudices.
My daughter, home or a long visit during the summer teaching break, was asked to carry out a bag of trash after a late dinner recently. The shortest distance led from our home to a detached storage building, via a path made of large concrete paving stones. It was between dusk and darkness, but the day's afterglow provided enough light to illuminate the short trek.
But not, apparently, enough light to see the toad sitting motionless on one of the paving stones. You can guess the outcome of her next step; fatal for the amphibian and traumatic for her. Her return from the uncompleted trash hauling errand was announced with something just short of a scream, and an urgent demand that I bring a wet cloth and wipe the toad guts from the bottom of her foot. For the rest of her stay with us, venturing out after dark was been met without enthusiasm, even when outdoor floodlights illuminate her route.
They say that good things often come in multiples. An evening or two later I was wrangling hoses and lawn sprinklers in the course of watering newly-laid sod, and a field where grass seed sprouts were poking up. When the timer on my smartphone signaled it was time to move the sprinklers, I went outside to put on shoes to rearrange the hoses. I felt something in the bottom of my shoe, turned it upside down and out fell a very-much-alive Anaxyrus americanus, a common toad. I didn't scream, but might have recoiled a little; my daughter gave a shiver and aid "yuck!" when I told her.
By all appearances, the closest relatives to toads are frogs. Both begin life as eggs laid in the water, which turn into tadpoles and breathe through gills like fish until they develop legs, their tails shrink and their heads become distinct from their bodies. In their mouth is a tongue that is not only capable of flicking out faster than the eye can see, but is coated with a sticky saliva that grips a hapless insect as the tongue retracts and pulls it into the amphibian's mouth. Worms and snails may be on the menu, too, but insects are at the top of the list. Frogs generally have a longer tongue, but both frogs and toads are experts at this deadly skill.
I can't speak for everyone, but I think it's safe to say that that the general public has greater fondness for frogs than for toads. One reason may be the old wives' tale about getting warts if you touch a tad, for which there is no scientific evidence. Toads do, however, secrete a substance that makes their skin bitter (which some think could be an irritant if transferred to the eyes) so relatively few predators bother with them.
Perhaps frogs are less off-putting than toads for some of us because we see them more often, generally when we're near water, which — for the average Minnesotan — is often. Then, too, there is that classic Americana image of little boys and frogs; though my wife — when she was young — collected frogs to sell to fisherman, evidence of both bravado and business sense.
Frogs, unlike toads, have many predators, from fish to herons to snakes, ducks, gulls, raccoons, mink, otters, hawks and no doubt more. Frogs' lifestyle of living near the water, actually IN the water from time to time, make them available to a wider variety of predators, including the aforementioned fish. During the heyday of live bait, live frogs were commonly used by anglers, often those pursuing bass. You can, from time to time, find a contraption known as a frog harness, of which over the years there have been several styles. All were designed to hold a frog, typically to be cast and retrieved, and armed with hooks at key locations in the event a fish was enticed to strike.
But the artificial lure makers were just as intrigued by the possibilities a frog presents for catching fish, so many different lures were painted in a "frog pattern;" generally green, spotted with black above and cream to white underneath. Hula Popper, Jitterbug, Flatfish, Lazy Ike and other lures were painted with this pattern, along with other standard patterns (the most universal being red and white).
And of course there is the Scum Frog of more recent design (not to be confused with the Dutch-American disc jockey, producer and music artist), a soft, rubbery lure that is intended to be cast and retrieved, and is of comparatively weedless design.
Few of us have occasion to see tadpoles, whether of the frog or the toad variety. This transformation from a fish-like creature to a hopping, land-dwelling amphibian is really a minor miracle, and a great example of Nature maximizing the use of resources in the circle of life. But moving from water to land during a life cycle is not unique to frogs and toads. Insects, such as dragonflies and mayflies, do it. Even we humans dwell in a sack of watery fluid for nine months, before we become air-breathing mammals.
One thing is certain, however, there is no human-to-frog-and-back-again morphing, the famous fairy tale by the Brothers Grimm notwithstanding.