Are amphibians on land not fully adapted

Amphibians - between water and land

Frogs: powerful voices

What distinguishes frogs?

Characteristic of frogs are the long hind legs, with which they can jump far and purposefully, their sticky folding tongues, which they cleverly use when catching prey such as flies or other insects, and in the males of many species the sound bubbles, which act as a resonance body and theirs Amplify calls. Because whoever croaks the loudest during the mating season also attracts the most females!

The eggs of the frog, which in addition to the frogs also include toads and toads, are almost always fertilized outside the body. When mating, the male therefore clasps the usually somewhat larger female from behind and inseminates the emerging spawn. Since the skin of the females is very smooth, calluses, pads or thorns have formed on the hands of many male frogs and toads so that they do not easily lose their grip when mating.

Frogs have numerous enemies: for example storks, herons, turtles, snakes and some bats have them on their menu. However, they are much more affected by the destruction of their habitat by draining wetlands and applying pesticides.

By the way: One of the approximately 4,000 species of frogs described to date has a tail like newts and salamanders, even in the adult stage: the tailed frog (Ascaphus truei).

How do frogs survive long periods of drought?

Among other things, by digging into the ground, such as the example of the water reservoir frog (Cyclorana platycephala) shows, which is at home in the hot Australian arid regions: it buries itself deep in the ground and surrounds itself with a layer of sloughed skin cells, which protects it from drying out. In addition, it stores a lot of water under the skin and in its body cavity. Only after heavy rainfall does the "rain frog" come to the surface to eat and reproduce.

Some species of frogs, however, are completely restricted to the water as a habitat, such as clawed frogs, comb toads and numerous real frogs. In the case of other terrestrial frogs, however, there is a trend towards significantly shortening the larval stage in the water. North American blade roots (genus Scaphiopus). Tadpoles hatch after just two days from the spawn, which is deposited in puddles that dry out quickly, and turn into finished frogs within twelve days.

Who carries a "womb" on their back?

The comb toad, up to 20 centimeters long (Pipa pipa), it shows a very strange breeding behavior: After the male has fertilized the eggs in the water, it forces them into small skin pockets on the back of the female. There the tadpoles hatch and grow until they finally break free from the narrow chamber as tiny young frogs (or toads). The South American Darwin nose frogs (Rhinoderma darwini), on the other hand, the males are responsible for the brood they harbor in their sound sacs. The group of comb toads is one of the most primitive and at the same time most peculiar frogs, because unlike all other frogs they not only lack the tongue, but they are also flat like a pancake.

By the way: Before the development of chemical urine tests, frogs were used as a natural pregnancy test, so to speak: the females of the African smooth-clawed frog were injected (Xenopus laevis) the urine of a pregnant woman, this is how they expelled their eggs. Since these tests were mostly carried out in pharmacies, the frog was also called "pharmacy frog" in Europe.

Is frog skin poisonous?

In some cases even highly poisonous, as the example of the poison dart frogs shows, the poison of which the Colombian Indians use for their blow arrows. These frogs, which are between 1.5 and 6.2 centimeters tall and live in the Central and South American tropics, have several names in everyday language: Based on their way of life, they are called "tree climbers", due to their colorfulness as " Color frogs "and called" poison dart frogs "because of their special use.

Unlike most frogs, these brightly patterned, shock-colored dwarfs are active during the day, because their blaze of color would be useless in the darkness of the night. Of course, it has a purpose: to warn predators of the highly toxic glandular secretions. At the yellow leaf climber (Phyllobates terribilis) For example, even touching it leads to poisoning.

By the way: The tropics are home to a particularly large number of beautifully colored frogs, such as the golden frog (Mantella aurantiaca) from Madagascar - an orange-red patch of color in the green surroundings of the rainforest. No less fantastic are the Central and South American glass frogs (family Centrolenidae) such as the naked-bellied glass frog, which is only about three centimeters long (Centrolenella colymbiphyllum): Through its transparent abdominal skin you can see the internal organs and see the heart beating.

Toad or frog: how can you tell them apart?

Typical of toads is, on the one hand, their dry, warty skin, which protects against excessive evaporation. On the other hand, unlike frogs, toads have no teeth; however, their tongue is well developed. In general, toads are more plump and stocky than the more graceful frogs; they also have shorter and less muscular hind legs in relation to their body length. That is why they are not as capable of jumping as their more graceful relatives. Toads are also less bound to water than frogs and often only go to water bodies to spawn. Most of them stay in the country and are usually only active during the night.

Real toads (family Bufonidae) occur in over 360 species in the temperate and tropical zones of Europe, Asia, Africa and America. More than half of them belong to the genus of toads (Bufo).

By the way: it's a myth that you get warts when you pick up a toad. Nevertheless, one should wash one's hands after touching a toad, because the animals can excrete a poisonous secretion from the bean-shaped, glandular skin thickenings behind the eyes, the so-called ear glands. This irritates the mucous membranes and, when it gets into the bloodstream, acts as a strong poison.

Why do toads have to migrate?

Because they depend on water for their reproduction. Many motorists are familiar with this scene: suddenly in the spring masses of frogs and toads appear on roads near bodies of water. They come out of their winter quarters and are on their way to their spawning grounds. They cover distances of up to one kilometer a day. The common toads begin to mate as they migrate, so that the larger females have to carry the males piggyback on. When they arrive at the pond or pond, the females lay their spawn after a few days, which is then inseminated by the male. So that the animals can safely pass roads, tunnels are often created in dangerous places or toad fences are erected.

Where did a toad become a plague?

In Australia. In 1937 the cane toad, up to 25 centimeters long and weighing up to 500 grams, was introduced there (Bufo marinus) to use them in pest control. The voracious animals were released in sugar cane fields, among other places, where they were supposed to fight rats and insects. But in the meantime the toad, which can spray its poison over 30 centimeters, has multiplied so much in its new home that it has become a nuisance for the local fauna, but also for pets and humans themselves.

This applies to the representatives native to our latitudes - common toad (Bufo bufo), Natterjack toad (Bufo calamita) and green toad (Bufo viridis) - fortunately not too. But they too produce a poisonous skin secretion that is used as an effective remedy against predators. If common toads are attacked - for example by a grass snake - they stretch themselves up and puff themselves up in order to appear as large as possible. By the way, your most dangerous enemy is the toad fly (Lucilia), the larvae of which nest in the nasal passages and in the brains of the toads after hatching and destroy the tissues so that the animals perish.

What is the doom reflex?

In the toad reflex, the toads show their noticeably brightly colored underside. This is also how the local red-bellied toads react (Bombina bombina) and yellow-bellied toads (Bombina variegata) at risk: If the animals feel threatened, they bend their backs and raise their arms and legs so that the colorful belly side becomes visible. In addition, toads can secrete so much poisonous secretion in danger that they appear "soaped" and are not so easy to grab.

Do all frogs croak the same?

No, each species has its own "song". This ensures that the right partners can come together even in a body of water in which several species make music together. Incidentally, it is the males who set the tone for the frogs, the females remain largely silent. When calling, the male presses air from the lungs up through the larynx, causing his vocal cords to vibrate while keeping his mouth and nostrils closed. The sound produced in this way is amplified by one or more sound bubbles, which are designed as skin pockets on the floor of the mouth or in the corners of the mouth. The pitch within a species depends on the size of the animal. In this way, females who are ready to mate can get a "picture" of the advertising male by listening carefully, and rivals are put in a position to assess the strength of their competitor.

Did you know that …

Amphibians can get quite old? Tree frogs can reach a maximum age of 22 years, pond newts 28 and common toads about 40 years, and giant salamanders even live 55 years.

there is a 65 kilogram salamander? It is the Chinese giant salamander (Andrias davidianus), which is up to 1.50 meters long.

Did you know that …

Toads belong to the disc bunch? The name refers to their disc-shaped tongue, which is attached to the floor of the mouth and therefore cannot be folded out.

one once called snakes as "toads"? This linguistic usage was to be found mainly up to the 17th century. With Jacob Grimm, the grass snake hid behind a "toad" and with Alfred Brehm the blindworm.

What makes a toad man a woman?

The so-called Bidder's organ, a stunted ovary, which, when the testicles are removed, develops into a functional ovary and thus turns the male into a female - a classic example of the fact that in vertebrates the sex is largely due to the suppression of the of the opposite sex is determined.