The Bullfrog Essay, Research Paper
I was amazed to find out just how ancient frogs are. For 190 million years, the ancestors of modern frogs have roamed (if not ruled) the earth, looking much the same as they do today. This means that at one time when there was a huge dinosaur eating a plant, there could have been some type of frog down by its feet. About 3,800 species of frogs and toads have developed since the dinosaur days. The secret to their success is their amazing adaptability. Frogs have evolved to live in a large variety of climates. They can be found just about anywhere there is fresh water- on all continents except Antarctica. Though they thrive in warm, moist tropical climates, frogs also live in deserts and high on 15,000-foot mountain slopes, and of course, here in New England.
They can be so adaptable because they are cold blooded, which means that their body temperature can change along with the temperature around them. When temperatures drop, some frogs dig burrows underground or in the mud at the bottom of ponds. They hibernate in these burrows until spring, perfectly still and scarcely breathing. A frog s skin also plays a big role in their survival. It is through their skin that they both drink and breathe. Frogs don’t swallow water; they get all the moisture they need through their skin, which must stay moist. If it dries out, oxygen can’t pass easily through it and the frog can suffocate. Frog skin secretes mucus that helps keep it moist. Even so, their skin tends to dry out easily, which is why they usually stay near bodies of water. About once a week, frogs shed their skin. The process begins with the frog doing a lot of twisting, bending, and stretching to loosen the old skin. Then the frog pulls the skin over its head like a sweater and usually eats it.
Two other parts of the frog have helped it to survive all these years as well. First, the hind legs of the frog, which enable some frogs to jump twenty times their body length. This would allow them to quickly get away from any predators. A frog’s two front legs have four toes each, while the back legs have five toes each. Most aquatic frogs have webbed back feet to help them swim, another way to get away from an enemy. Frogs that live on land tend to have shorter legs for walking and climbing, but are still able to swim in water.
The other part of the body that help them survive so long are their big, bulging eyes, as they are able to see in all directions. Frogs’ large eyes see a wide range of colors and also see well in dim light. This not only increases their chances of surviving a predator, but also decreases the ability of their prey to get away. Since they have such big eyes, they are able to see their own prey and target them for food. It has been found that when a frog sticks out its tongue to catch an insect or other food source, it briefly closes its eyes. The frog must therefore, know exactly where its target is, and aim, before the tongue leaves the mouth. The positioning of the eyes, on top of the head, allows a frog to sit in the water with only its eyes and nose above the surface, so they do not have to leave the water for food. Frogs eat almost any live prey they can find, including insects, snails, spiders, and worms, or small fish. Their tongue is long and sticky and takes less than a second to roll out, adhere to prey, and roll back into the frog’s mouth.
Their mating call is sometimes called an advertisement call. It is made by the male in the water and allows the females to know which is her species. Each species has a different type of mating call. This is difficult to decipher around a pond of noisy frogs. When they mate, the male frog climbs onto female’s back, grasping her with his front legs. As the female lays her eggs, usually into water the male release sperm that fertilizes them. There may be anywhere from one to hundreds or thousands of soft, jelly-covered eggs. The eggs hatch within three to twenty five days, and few will survive the difficult trip to adulthood. Among most frogs, a tadpole will hatch and spend the next few years growing into a frog. The changes begin when the hind legs sprout. Soon after, lungs develop and the front legs appear. Meanwhile, the tail gradually shrinks. Just before becoming a frog, the tadpole’s gills disappear. The tiny froglet emerges from the water with just a stump of a tail, which soon disappears.
The observations that I took did little justice to the complexity of Rana Catesbeiana, the bullfrog. Frogs have been living on this Earth for millions of years and have perfected their lifestyle throughout that time. The amazement of these creatures is that they can survive well in nature, but can also be house pets for children to play with and learn from. There are myths that have surrounded frogs and superstitions that have risen over the years. One that comes to mind is that if you kiss a frog, you will get a wart. Like many superstitions and legends, no one knows for sure where that one came from, but watching these cute little amphibians, I highly doubt that they could do any harm.
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