The RRRRRRRRiveting Life of
Amphibian. One of those words we learned the meaning of some years ago. A cold blooded critter, never much warmer than its environment, usually having an aquatic, gill-breathing, legless larval stage, including a tail – which we refer to as a tadpole – then later developing lungs.
Lacking effective moisture barriers in their skins, most amphibians must submerge themselves in water frequently or live in a moist environment to avoid dehydration, so they don’t venture far from the liquid.
They’re always fascinating creatures to see. And a walk-about at The Nature Conservancy’s 4,000-acre acquisition on the shoreline of Port Susan (Bay)* reveals several of the more mature tailless amphibians we call frogs – Pacific Tree Frogs, Hyla regilla – the most abundant of all the tailless amphibians in our region.
There apparently is a great deal of variation in coloration in Pacific Tree Frogs, depending on the background color. They can actually change to colors similar to their habitat – to less showy gray shades or tans, or perhaps bronze or brown, or near-black when in such hued places. They are often marked with dark patches on their backs – pale underneath.
But most fittingly, along the reserve’s dike walk, several Pacific Tree Frog sightings are standouts – bright emerald green, no splotches – the color ever so vivid and appropriate as the emerging plant life making up the background trailside consistent with young green shoots of grass and other green vegetation.
They each had a white-bordered dark streak running backward from above the mouth region (general references say through each eye). Their bright color and markings remind me of brilliant, tropical Poison-Dart Frogs I’d seen several years previously in Costa Rica.
Probably about two inches in length, the several frogs seen had long slender legs, toes with very little webbing between them, but with terminal little round pads. These bulbous items can create a suction, serving them well when clinging to slick surfaces such as trees wet with moisture or rain.
As far as dietary consumption, tree frogs primarily dine on insects, and for this purpose they have sticky tongues.
Outside their breeding season, they are quite cosmopolitan in their choice of homes: woodlands, pastures, even urban areas. But during breeding season, as spring approaches, the tree frogs gravitate to shallow wetlands – places important to many life forms.
And this is a time when the males will croak like mad nightly for several weeks to attract females. The calls are of the “ribbit, ribbit” variety – sent forth every two or three seconds.
For amplification the males have a throat sac which resonates when blown up – inflated sacs that can end up being three times the size of their heads!
Are the frogs’ trios, quartets, even full-blown choruses appealing? Are their relatively huge throat sacs considered comical? Or are they perceived as handsome? Guess it depends on whether one is a female tree frog seeking a suitor.
But the sounds are ones movie-makers for decades have often put into the soundtracks of their offerings. Hence many think that numerous frog species “ribbit”, but the Pacific Tree Frog is actually the lone “ribbiter”.
Written by Pat Nash, February 2005
Beach Watcher Class ’94
* Editor’s Note: Access to the Nature Conservancy Port Susan Bay Preserve is by permission only – 2008.