Painting Using Negative Shapes
News for November
Frogs and Toadsby Jenny Heidewald
Frogs and toads have shared the planet with humans as far back as human history extends, and beyond. With their large eyes, their love of and need for water, their quadrupedal bodies and colorful skin, and their eerie voices, frogs and toads are both distinctly alien to humans yet oddly similar at the same time. Human cultures throughout history have sought stories to explain these creatures who share our world, or to incorporate them into folklore or mysticism; in almost every case, the amphibians become creatures distinctly human, and yet possessed of unusual powers. They are seemingly inhabitants of a secret natural world.
Belonging to the order Anura, frogs consist of approximately 5,000 species, with more being found each year. As amphibians, they are cold blooded, with the exception of Antarctica, they live on all continents. They are an important piece in the circle of life, from egg through adulthood they are potential food for many creatures. Their journey from egg to full-grown adult is looked on with amazement; it is like watching evolution in fast forward.
Frogs and Toads in Culture
Frogs are all through our cultures: Kermit the Frog, The Wind in the Willows, by Kenneth Grahame, Michigan J. Frog from the famous "One Froggy Evening" cartoon and later a mascot for the former Warner Brothers' US TV network, and who can forget the Bible's plague of frogs with which the Egyptians contended? Egyptian mythology also has a frog headed goddess, Hecket, who with her husband created humans and other gods. The ancient Chinese believed that the eclipses of the moon were caused by a frog eating it, and the frog and toad are featured in Native American stories and are carved on totems. Also, the "princess and the frog" stories, where a witch has changed a handsome prince into a frog, a form from which he can only be changed back by the kiss of a princess.
In the middle ages, toads were thought to be witches' familiars, as well as ingredients for strange witches' brews. Interestingly enough, as a sort of saving grace, the toad was also believed to have a precious stone embedded in its head, called a toadstone. This stone was touted to have magical powers, such as curing stomachaches or cramps, or detecting and neutralizing poison, rather like the horn of a unicorn.
It seems to be a theme with many animals that humans would superstitiously use them for supposed cures. Some toads and frogs are also used to get "high"; deliberate exposure to the skin secretions of certain species of toads will induce psychedelic hallucinations. The poison dart frog, on the other hand, secretes such powerful poisons that Choco Indians use the secretions to tip darts or arrows, which would paralyze or kill its victims. This poison can retain its potency for up to a year after application to the dart tips.
Frogs have traveled down a different path in the human psyche; instead of being hated, they are considered good luck, for example, if one comes into your house, or if you see one on the road. They are eaten by many people, and even get called "mountain chicken" by some! In most cases, it is only the legs of frogs, with by far the most meat, which are eaten. The Australian aborigines use the water-holding frog, (Cyclorana platycephalaas), as a source of water; when this frog is squeezed it releases a bladder of the life-saving liquid.
Sadly, the most common use of the frog in the Western world until recently was the dissection of frogs for anatomical study in schools. The African clawed frog (Xenopus laevis) used to be used as a way to confirm pregnancy in humans; the frogs would lay eggs when it encountered a hormone present in pregnant woman.
The largest frog in the world is the West African Goliath frog (Conraua goliat), which may exceed, from tip of the nose to "tail", 12 inches, or 304.8 mm. There are a couple of contenders for the title of smallest frog, the Brazilian gold frog (Psyllophryne didactyla) and the Cuban Monte Iberia Eleuth (Montelberia eleutherodactylus iberia), are both smaller than half an inch. Most frogs and toads are within the size range of 3/4 inch to three inches, or 20-80 mm.
While all toads are frogs, not all frogs are toads! So what are the differences between frogs and toads? In general, frogs are moist and are fast, agile jumpers; they need to stay close to water to help keep their skin moist. Frogs get most of their oxygen and water through their skin, and a few species don't have lungs at all, they stay in the water. Many frogs have dorsolateral folds, which are two lines of raised skin that run from behind the eyes, parallel to each other and separate the back from the sides.
Toads tend to be rounder, with stumpier legs and dry skin appearing to be covered with warts. A popular, but completely untrue, bit of folklore is that handling toads would give one warts; the so-called "warts" are an accumulation of mucus glands and poison glands that are in the skin and do not cause warts in human skin... Most toads have pronounced parotoid glands, these wart-like protuberances, located behind the eye and above the ear, secrete poison when the toad is endangered. They are able to handle being away from water for longer periods, and walk or hop as opposed to jump.
Frogs and toads generally come in brown shades, though there are many rainforest frogs with brilliant and amazing colors. Most typical is green, but there are also yellows, oranges, reds, blues, and different combinations with black.
There are a few different pupil shapes, vertical, horizontal, round, and triangular (also referred to as "heart" shaped). Some frog eyes are so dark you can't see what shape the pupil is. These pupil shapes make the frogs eye sensitive to different sorts of movements; for example, a vertical pupil can see horizontal movements best. Like birds, frogs and toads have a nictitating membrane, which is a semi transparent layer of skin that the animal uses to protect the eye. Near the eyes is the tympanum, more commonly known as the eardrum, for protection this is covered with a layer of skin.
One of the trademarks of frogs and toads are the vocal sacks. Balloon-like and mostly used for mating calls, these come in different shapes: single, which can come in round or sausage shapes, even double or bilobed. These vocal sacks are slightly transparent, and you can see some veins when they are extended.
Most if us are used to seeing the regular pond tadpole shape, but there are more streamlined ones that are adapted to fast flowing water, and some even have a mouth adapted to feed from the surface of the water. As the frog develops it gains various limbs, and eventually the tail is reabsorbed into the body.
While most species of aquatic amphibians lay eggs into the water where they are fertilized outside of the mother's body and left behind, there are a few that have different ways of ensuring that their young get the best start possible. In some species of toads, the males carry the eggs wrapped around their back legs until they are ready to hatch. The male Darwin's frog(Rhinoderma darwinii) guard the eggs until they start to hatch, whereupon he takes fifteen or so into his mouth and they live in his vocal sack, eating their egg yolk until fully developed. One of the most unusual is the tongueless Amazonian toad (Pipa pipa). The female of this toad has amazing skin on its back that swells up around her eggs, which the male has helped put on her back. The babies then live in this protective honeycomb, eating egg yolk, until they are fully formed and leave their mother. The mother's skin sheds after the babies are out, and is then ready for her next batch of babies.
In general, frogs and toads have four fingers and five toes, and they usually have the same amount of bones and joints that a human does. Notice that the front feet turn inwards, making the outer finger point forward. These amphibians have different feet developed to suit their environment and lifestyle. A tree frog, for example, has knoblike toe tips, for better gripping of twigs and limbs as they navigate their leafy terrain. Bullfrogs, which spend a lot of time in the water, have large webbed hind feet. There is even a "flying" frog species (genus Rhacophorus), which has very long feet and large membranes between to toes to assist it in its unorthodox, last ditch, method for escaping from predators. This frog leaps from its perch and glides, rather like a flying squirrel. The back leg of the frog is interesting due to the four sections. The first two correspond with the thigh and shin/calf bone of the human, and the third and fourth sections correspond with the human ankle and foot. The tarsal (anklebone) is elongated to give the frog a better spring.
There are a myriad of different colors, shapes (frogs that look like leaves!) and interesting habits that I haven't been able to do justice here. I encourage you to discover more about the strange and wonderful world of frogs and toads online and through books.
The photos are from The U.S. Fish and Wildlife Service's National Digital Library
How to Draw
How to draw a frog 1
How to draw a frog 2
How to draw a frog 3, from What to Draw and How to Draw It, by E.G. Lutz.
How to draw a toad
Frog skeleton movie
Frog, by Thomas Marent
Frogs & Toads of the World, by Chris Mattison
The Nature of Frogs: Amphibians with Attitude, by Harry Parsons
Frogs: Inside Their Remarkable World, by Ellin Beltz
Frogs: A Chorus of Colors, by John L. Behler and Deborah A. Behler
The Frogs and Toads of North America: A Comprehensive Guide to Their Identification,Behavior, and Calls, by
Lang Elliott, Carl Gerhardt, and Carlos Davidson
Frogs: A Wildlife Handbook, by Kim Long
Jenny Heidewald is one of those self-taught artists that has been drawing since she was little; she remembers the exact moment she decided that she wanted to be an artist. Interestingly enough, it was while watching her mom draw the hand of God reaching from the clouds to His followers. Jenny was floored, it seemed to be magic, an image appearing out of nowhere. She thought, "I want
to do THAT!" In addition to writing for EMG-zine, Jenny is a prolific artist who has worked in many mediums. Her current favorite technique is working with colored micron pens, and coloring either with watercolor or Photoshop. Jenny lives in Maryland with her husband. Please check out her Sketchfest, Portrait Adoption, Deviant Art, and Elfwood pages.
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