Less than three inches long with paper-thin skin, wood frogs might seem like one of the most unlikely creatures to be able to endure Alaska’s frigid winters. However, it turns out they take a rather Zen-like approach to the cold, becoming one with their environment by freezing along with it.
For as long as seven months, up to 60 percent of their bodies freeze solid. They stop breathing. Their heart stops beating. This semi-frozen state allows them to survive temperatures that that dip below zero, explains Brian Barnes, researcher and director of Arctic Biology at the University of Fairbanks, Alaska. Come spring, they thaw out and come back to life.
Scientists have known for decades that the amphibians deep-freeze when the mercury drops. However, this is the first time they’ve been observed surviving such low temperatures or for such a long stretch of time. It’s also the first time that researchers might have an explanation for why these critters don’t just turn into permanent frogsicles…
Well, actually, it takes more than a bit of rain to get the gopher frogs, Rana capito, up and moving. Truth be told, a bit of rain may get them near the mouths of the burrows in which they are usually secluded, but it takes a whole lot of rain to get them out of and beyond their entryways.
The gopher frog may be the most seldom seen of the “common” southeastern frogs (in the United States).A species of sandhill ponds, it spends a goodly percentage of the daylight hours an arm’s length or further back in the burrow of the gopher tortoise. When in the ponds the snoring calls of the gopher frog are unmistakable.Like most frogs, the gopher frog is capable of considerable color change.
Often having a ground color of light tan to light brown with irregular dark spots and bars when warm, they darken considerably when cold. When cold they may be nearly black. Then the darker markings are all but indiscernable…
The American Bullfrog (Rana catesbeiana) is North America’s largest frog, growing up to 6 inches (15 cm) from nose to rump. Their large size allows them to be opportunistic predators of anything from insects to snakes to rodents or small birds.
Very similar in appearance to other Rana species, including the Green Frog (R. clamitans), it has two unique characteristics: it lacks the prominent back ridges (called dorsolateral folds) that other frogs sport, and its tympanum (the flat circle behind the eye, which is actually its eardrum) is always as large as (females), or larger than (males), the eye.
Bullfrogs were originally native to eastern and south-central North America, but have been introduced to the rest of the continent, as well as several other parts of the world, partly for their legs as a food item.
The Iberian frog (Rana iberica), like most of its hopping ilk, is commonly found above ground, dwelling among the streams of Portugal and Spain. But new research shows the animals can, and do, make a living underground.
The study found that Iberian frogs can breed and live their entire lives in cavelike chambers, the first time this has been seen for a frog in Western Europe. The creatures were observed breeding in underground drainage compartments built beneath Portugal’s Serra da Estrela Natural Park; aboveground the animals are also found in “small ponds, humid meadows and soaked fields,” the authors wrote in a study.
Although frogs and toads are known to inhabit caves during certain parts of their life cycles, or to seek their moderate, consistent temperatures, no frog in the world is known to live solely underground, according to the research…
“Indian Valley Bullfrog (Hoplobatrachus tigerinus), Kalaiya, Nepal. This large striking frog is found in the lowlands of some of SE Asia and the Mideast. Recent studies have ascertained that it’s probably a complex of several species.”
(this specimen is an unusual amelanistic individual, this coloration is not normal)
The European Common Frog (Rana temporaria) is found throughout much of Europe. Adults have a body length of 6 to 9 cm (2.4 to 3.5 in) and vary in colour, with the ability to lighten and darken their skin in order to match their surroundings. They will feed on any invertebrate of a suitable size and, apart from the breeding season, live solitary lives.
This wood frog, the species of frog known to live further north than any other species of frog, can stay frozen all winter until it thaws out in spring. Patrick explains how the frog is physiologically able to freeze and thaw it’s body. Footage from our Rite of Spring episode.