It’s A Frog’s Life
May 21, 2008
Tim Keyes is a Wildlife Biologist with the Georgia Wildlife Resource Division, focusing on non-game birds. He has been involved with wildlife education, research and conservation for the last 15 years.
This post originally appeared in Creation Care Magazine.
Long before the first migratory songbirds return, even when snow remains on the ground, the winter breeding frogs can be heard as an early promise of the return of spring. I had often enjoyed this evening chorus of frogs and toads, and knew several of the more common species, but had never mustered the time to learn the 40 or so species that occur in Georgia. The initiation of the North American Amphibian Monitoring Program (NAAMP) in Georgia finally spurred me to learn the frog calls of the southeast and it has been a real pleasure. The calls of our frogs range from the beautiful rapid whistles of the Birdvoiced Treefrog to the bizarre nasal bleat of the Eastern Narrowmouth Toad and frantic Morse-code –like tapping of the Pine Woods Treefrog. Kids love the “bodily function” calls of many species (the ‘snore’ of the Gopher Frog, and ‘vomit’ of the Eastern Spadefoot).
Learning the calls of your local frogs is a perfect activity for anyone who likes the idea of birding, but hates getting up early, as frogs really only get cranking after dark. This fact allowed me to convince my wife to join me on my frog survey route, something she has never done with bird surveys. There are also far fewer frogs than birds to learn in any one part of the country. For some, hurdles must be cleared to fully enjoy frogs. From an aversion to their sometimes slimy skin, to (false) rumors of warts, frogs and toads often suffer from unfair perceptions. Even the official term for studying reptiles and amphibians- herpetology—refers to the study of “creeping things”—a lamentable description of the diversity encompassed by the word.
Frogs can be found in most parts of the globe excluding the coldest and driest parts of the world. Species such as the spade-foot toads can inhabit desert environments they must remain buried in a cocoon-like case for months to avoid drying out. Others, such as the wood frog, lives north of the Arctic Circle and only survives winter by letting intercellular fluids in their bodies freeze, keeping cells and organs from freezing by producing biological “antifreeze” in the form of extremely concentrated glucose. These are clearly extremes and the vast majority of the worlds frogs live in warm humid climates.
Brazil holds the distinction of having the greatest diversity. While most frogs lay their eggs in water (where the eggs begin the fascinating process of metamorphosis from egg to tadpole to adult frog) there are significant variations on this theme, including the “gastric-brooding” Australian frogs that swallowed their young, letting them develop in their stomachs (sadly, this species is likely extinct). Other species like the Suriname Toad actually force their eggs into their spongy skin, where they form protective cysts and develop. Frogs range in size from the monstrous Goliath Frog, which can weigh 7 pounds, to the minute Brazilian gold frog, which full grown barely exceeds 1/3 of an inch in length.
Lacking protective scales, fur and sharp claws, frogs exhibit some remarkable defenses against predators. The “warts” on toads are actually parotid glands that contain a distasteful milky toxin to protect them from predators. Toxins on frogs and toads range from mild irritants to hallucinogens, nerve toxins and vasoconstrictors. As long as you don’t put them in your mouth or handle them with open wounds, you should be fine. The skin of some of the renowned tropical “poison-dart” frogs contain some of the most toxic natural substances known. Their high toxicity allows them to sport brilliant colors and brazenly forage on the forest floor in broad daylight, which is quite a sight if you have the good fortune of visiting the tropics. You certainly don’t need to travel to the tropics to enjoy frogs however, as many species can be found much closer to home.
Frogs can be enjoyed with all the senses. Since frogs live in a primarily auditory world you will typically hear many more than you will see, and my primary pleasure is to listen to the raucous clamor of calls. If you live near standing water, enjoying frogs can be as simple as sitting outside and listening. If you live high and dry, you may need to travel, but you shouldn’t be far from a pond, swamp or ephemeral pool for an evening visit. The best time to listen is on a warm spring evening after rain. In winter or early spring, you will primarily hear cricket frogs (genus Acris) or various species of chorus frogs (genus Pseudacris). These include the well known spring peeper. As spring and summer progress the diversity will increase dramatically.
If you want to move beyond listening, grab some boots, a flashlight and some patience, for simple searching will often yield close views of a variety of species. Especially enjoyable are the tree frogs that will often allow you to get very close as they call from shrubs and small trees near the water.
To study the remarkable transformation of developing frogs (eggs to tadpole and frogs), you can collect a cluster of eggs and keep them in an aquarium. This is a fantastic activity for kids. I have rarely seen young boys and girls enjoy themselves more than at a pond’s edge with a bucket and a net, and no squeamish fear of muddy feet. Make sure when handling frogs at any stage of development to keep your hands free of insect repellent or sun block, as it can traverse their skin easily. Collecting eggs in the wild and returning the frogs to the same place is far superior to buying eggs. If you purchase frogs eggs or tadpoles to raise, do not release them into the wild, as they are likely not native to your area.
Many species of frogs require standing water without fish, as fish eat the vulnerable eggs and tadpoles. This means that ephemeral and vernal pools that dry up in summer are critical to a number of frog species. If your passion for frogs continues to grow, think about putting a small pond in your yard. Withstand the temptation for fish, but provide some native vegetation and see what turns up.
So, before summer comes, take a nice warm humid evening and go out in search of frogs. I hope you will be serenaded by one of the auditory wonders of the natural world, a deafening chorus of frogs and toads on a damp spring night. With a little practice, you will be able to identify many of the singers in the
choir.
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The Minnesota leopard frog is coined the “envionmental canary in the coal mines” it is past due to clean up our air, water and soil.
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I love the way you blend your knowledge with storytelling and can pull it back to a universal application. Would you be interested in writing for our online magazine called Wrecked for the Ordinary?