Frogs referat





Frogs

Frogs are members of the Amphibian family, which are cold-blooded (poikilothermic) vertebrates. They differ from reptiles in their absence of scales and, for the most part, return to the water to breed. There are about 3,900 species of these tailless amphibians, or Anura. They are also called Salientia, including the frog and the toad.

Amphibians and reptiles together may be considered as a group called Herps, therefore, the study of amphibians and reptiles is called herpetology. The root word, Herp, is from the Greek basically meaning 'creepy crawly things that move about on their bellies.'

A group of frogs is called an 'army.'

MYTHS

Some Australian abortiginees and American Indians believe that frogs were the bringers of rain.




In India, frogs were felt to represent thunder in the sky. In Sanskrit, the word for 'frog' also meant 'cloud.'

In the country of China, instead of the 'man in the moon,' they see the 'toad in the moon.' The toad is considered one of the five 'poisons of yin.' Eclipses occur when the 'toad in the moon' tries to swallow the moon itself.

To the Japanese, frogs are symbols of good luck. One myth is that bullfrogs are descended froma great ancestor who could suck mosquitoes out of a whole room in a single breath.

Folklore has suggested that if the first frog you see in the string is sitting on dry land, you will shed as many tears as the frog would require to swim away. If the frog jumps into the water, that is even worse. You will experience a year of misfortune. A frog jumping toward you will signify that you will have many friends, but if it is jumping away, you will lose some.

To some unenlightened people, frogs and toads, mainly the latter, are evil incarnations of demons and devils.

Warts, as opposed to myth, are the result of viruses, not frogs and toads.

Batrachophobia-Fear of amphibians, such as frogs, newts, salamanders, etc. Ranidaphobia-Fear of frogs Bufonophobia-Fear of toads

FROG ENEMIES

Frogs have multiple enemies, including snakes, birds, and small animals like hedgehogs. Even other frogs can be enemies. The worst frog enemy is probably pollution, and frogs and important in measuring the health of the environment and in tracking ultra-violet radiation penetrating our atmosphere. Worldwide, frogs numbers have been diminishing, with many species nearing extinction.

FROGS and TOADS

All toads are frogs, but not the opposite. Frogs, to our common understanding, are the more than 400 species of the family Ranidae. They have 1) two bulging eyes 2) strong, long, webbed feet that are adapted for swimming and leaping 3) smoothe or slimy skin (frogs tend to like moister environments and 4) tend to lay eggs in clusters. They can be found on every continent except Antarctica.

Toads are members of the family Bufonidae, with more than 300 species. They have 1) Stubby bodies with short hind legs (for walking rather than hopping 2) Warty or dry skin (toads prefer dryer climates) 3) Paratoid (or poison) glands behind the eyes 4) Chest cartilage different from frogs 5) tend to lay eggs in long chains, although there are toads of the Nectophrynoides genera which bear live young. They can be found worldwide except for Australia, the polar regions, Madagascar, and Polynesia.

LIFE CYCLE OF THE FROG

Mating occurs by the male frog climbing on the female's back and grasping her 'around the waist' in an embrace called amplexus. Amplexus may actually last up to several days. As the female lays her eggs, the male frog fertilizes them.

Many, many eggs are laid, because most of the time, they will never survive. As the yolk divides and divides, something that resembles a tadpole begins to develop in the egg. After about 6 days, the egg hatches. The tadpole initially feeds on the residual yolk, which is actually in its gut. The tadpole is really fully developed. It usually attaches itself to floating weeds and grasses. It is not until 10-12 days later that it begins to feed on algae.

After about 4 weeks pass, the gills are gradually grown over by skin, eventually disappering. They develop very tiny teeth which help them grate food, turning it into soupy oxygenated particles. At 6-9 weeks, little legs start to appear. The head becomes more distinct and the body elongates. Dead insects and plants are added to algae as part of their diet. The arms begin to bulge out and appear, elbows first. At 9 weeks, the tadpole begins to look like a frog with a tail.



By 12 weeks, the tail has regressed. The frog grows from about 12-16 weeks they are full-fledged adults. (In some colder places, the tadpole stage may last throughout the winter.)

FEEDING

Some frogs have sticky tongues which can be used to catch bugs, 'flipping' from the mouth. Toads usually sneak up on their prey, and 'snap' at it. When a frog swallows a meal, his bulgy eyeballs actually close and go down into his head, helping to apply pressure to push the meal down the frog's throat.

HEARING and VOCALIZATION

Frogs hear using big round ears on the sides of their head called a typanum. It's size and the distance between them depends on the wavelength of the male frog's call. The frog's ears are connected to their lung, so when they hear noises, not only does the eardrum vibrate, but also the lungs. Many scientists believe that this is what keeps the frog from 'blowing out its own eardrums' with its loud calls.

Frogs vocalize by shutting their nostrils and mouths and squeezing their lungs, expanding their vocal pouches as a resonating chamber by air flowing over the vocal chords. Large frogs have deep, low frequency voices. Small frogs have high, chirping (high frequency) voices. In the cold, the frogs repeat their calls more slowly because the muscles controlling the sounds slow down.

What is a frog's sound in various languages?

Afrikaans: kwaak-kwaak Arabic (Algeria): gar gar Catalan: cruá-cruá Chinese (Mandarin): guo guo Dutch: kwak kwak English (USA): ribbit English (GB): croak Finnish: kvak kvak French: coa-coa German: quaak, quaak Hebrew: kwa kwa Hungarian: bre-ke-ke Italian: cra cra Japanese: kerokero Korean: gae-gool-gae-gool Russian: kva-kva Spanish (Spain): cruá-cruá Spanish (Argentina): berp Spanish (Peru): croac, croac Swedish: kvack Thai: ob ob (with high tone) Turkish: vrak vrak Ukranian: kwa-kwa

FROG FEET

Frogs have feet that are adaptable to their habitat. Tree frogs have sucker-like adhesive disks or 'sticky pads.' Frogs which swim have webbing between their toes. Frogs that burrow into the sand to keep moist in the heat have stubby, clawlike fingers. Frogs which 'fly' have parachute-like webbing which can act as an air brake when jumping from tree to tree.

LIFESPAN

In captivity, most frogs live between 4 and 15 years. Little is known about their lifespan in nature. Here are some lifespans in captivity.

Longest lifespan: European Common Toad-40 years Giant Toad: 7-24 years Green and Black Poison Dart Frog: 7-17 years Oriental Fire-bellied Toad: 11-14 years Ornate Horned Frog: 5-12 years

THE BIGGEST AND THE SMALLEST

The biggest frog is the Goliath frog, found in Cameron in West Africa. Their bodies can reach 1 foot long (and their legs are at least that length). It weighs as much as a large housecat, about 3.3kg.

The smallest frog is the Gold Frog or Brazilian. The adult measures 9.8 millimeters in body length (with legs drawn in).












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