Characteristics of frogs
Frogs are a genus of relatively small amphibians that range from just 8 millimeters to 30 centimeters . They are part of the group of anurans, or what is the same, tailless batrachians. However, despite not having this member in their adulthood, they do have very long and developed hind legs that allow them to make great jumps and move with agility.
These small animals not only defend themselves well on land, but are also adapted to living in freshwater environments and even in trees or underground. Although we can find them in almost any corner of the planet, the greatest diversity of frog species is found in humid tropical forests . In any case, they are one of the animals that best adapt to the environment in which they live, with the exception of the polar areas, where no frog species have been described due to their intolerance to cold.
Frogs in general are carnivorous animals , although there are also some types of omnivorous or frugivorous frogs . They normally feed on aquatic and terrestrial invertebrates, such as insects, arachnids and crustaceans, but also on small vertebrates, such as lizards or mice. When prey is close, the frog watches until it is ready and close enough to stick its tongue out and catch it. The prey is then stuck and is quickly eaten.
On the other hand, these amphibians are oviparous animals , that is, they lay eggs and normally deposit them in water. After hatching, the aquatic larvae or tadpoles, characteristic for having a tail and gills, survive in the water until they complete the metamorphosis that turns them into adult frogs.
Frogs are famous for their vocalizations . They have a wide range of sounds, especially varied at the time of reproduction. However, it is appropriate to comment that this famous “cruac” is, in general, more typical of males.
These amphibians stand out for having “shiny” skin. What really happens is that these beings are semi-permeable , which makes them susceptible to dehydration. That is why we usually appreciate these funny little animals on the shores of humid places.
Difference between frog and toad
Confusion between frog and toad is very common given the many characteristics they share. However, there is a clear difference between the two: frogs have smooth or almost smooth skin and a slender or athletic body, while toads have rougher or warty skin and a broader body. Likewise, the concept of frog refers to the genus Rana . Instead, toads are amphibians that belong to the genus Bufo .
What types of frogs are there?
Within the order of the anurans ( Anura ) and the family of the frogs ( Ranidae ) we find 24 genera that are currently recognized. One of them is the genus frog ( Rana ), considered that of “true frogs” a name that allows differentiating the species of this genus from others that contain the term “frog” in their common name and that do not belong to the genus frog. Thus, it is currently considered that there are 49 species of true frogs in the world.
Types of true frogs
Here are five species of true frogs :
1. Country frog
The field frog is endemic to Europe and Asia, adapting to all types of habitats, such as the tundra, forests or the steppe. It is reddish-brown in color and stands out for camouflaging itself especially well among vegetation. It measures between 5.5 and 7 cm. long and since 2008 it is in a situation of least concern according to the IUCN, the red list of species.
2. Northern red-legged frog
For its part, the northern red-legged frog is one of the types of frogs native to North America, spreading from Canada to the United States. We can find this species in calm waters of ponds, streams or ponds. It can reach 8 cm and it stands out for having a ready skin of brown or reddish color , accompanied by small black spots. It is also a species considered of Least Concern.
3. Iberian frog or long-legged frog
The long- legged frog is a species endemic to the Iberian Peninsula, which includes Spain and Portugal. It inhabits swamps, rivers and mountain streams. This little frog, about 7 cm. It is threatened by the loss of its habitat and will soon be classified as vulnerable if its population continues to decrease.
4. Vermilion frog
The vermilion frog , also known as the common frog, is endemic to Europe and Asia. It spends practically its entire life on land, however, it can submerge itself in water to breed or hide from potential predators. It is robust in appearance , measuring between 6 and 9 cm., And is brownish in color. It is a species considered of Least Concern.
5. Yellow-legged mountain frog
We finish the types of frogs of the genus Rana with the yellow-legged mountain frog , an endemic species of California, United States, which measures between 4 and 9 cm. about. It is generally yellowish in color with black and brown markings, but it can also have olive undertones. This species is in danger of extinction and, as a curiosity, it emits a defensive smell similar to garlic.
Types of non-true frogs
Although the species that we will mention below do not belong to the genus Rana , they are worth knowing for their enormous popularity:
1. Goliath Frog
The Goliath frog , as its name suggests, is huge, reaching up to 30 centimeters , which makes it the largest in the world. Still, their size largely depends on their diet and the location of the species. Other typical characteristics of the Goliath frog are its olive green color with varied and patterned shapes that allow it to blend in with its surroundings and its lack of vocalization. Thus, despite her good hearing, we will not hear this frog croak.
Although this species has become popular as a companion animal, we must know that its maintenance, especially complicated, and the loss of habitat are causing a significant decline in its population. For all this, it is currently in danger of extinction .
2. Glass frog
One of the most particular characteristics of this endemic frog from America is that its skin is transparent , so we can see its organs inside. In fact, if we look closely, we can even observe its little heart beating and pumping blood. This transparency brings a very positive associated advantage for the species, in certain sciences such as medicine, a great variety of reactions can be studied and observed without dissecting the animal.
Despite their main characteristic, these frogs have a greenish color and are very small, usually between 3 and 4 centimeters in adulthood. They are also arboreal amphibians, so they live high in the trees in forests of the Andes, Central and South America. There they feed on small insects during their nocturnal habits. It is a species that has currently been listed as a Least Concern .
3. Flying frog
Yes, this frog seems to fly thanks to its long fingers joined by a membrane that allows it to move through the air as if it had a parachute. This “flight” is carried out instinctively and brings great advantages in nature, such as going from one tree to another just by gliding. In addition to this, as can already be guessed, the flying frog is also arboreal and native to the Philippine Islands . It is also considered a minor concern.
4. South African black frog
Apart from being black, this strange frog measuring about 4 to 5 centimeters is plump, with tubercles and has a serious face. Native to South Africa, the black frog lives primarily in temperate forests, although its habitat and consequently the species is considered of less concern . Another curiosity of the species is that it can swell its body if the occasion requires it, such as, for example, to avoid being ingested by a predator.
5. Mossy frog
What best defines this frog, also known as “moss frog” is its amazing camouflage ability, which makes it almost invaluable in its natural habitat, such as in tropical and subtropical forests of Vietnam. This enormous advantage allows it to go unnoticed both in front of its prey and its predators. Its population is in decline and, once again, we note that it is one of the types of frog that is considered of least concern .
6. Red-eyed green frog
The red-eyed green frog is especially striking due to the colors that adorn its anatomy: green, blue, yellow, orange and deep blue, all accompanied by its bulging eyes. However, despite these characteristics, this frog is not poisonous. It is an animal considered a minor concern. It is a solitary nocturnal animal that is usually found in lowlands or high up in trees or shrubs in tropical forests found in southern Mexico, Central America, and northern South America.
Types of poison frogs
Although frog skins generally vary between green, brown and gray, there are certain species that present more striking colors such as red, yellow, black and blue to alert their predators of the toxicity they present. Here are some species of poisonous frogs.
1. Golden frog
This striking and attractive color amphibian that can appear harmless is considered the most dangerous and toxic vertebrate on the planet . The venom from the skin of a single specimen is enough to kill up to 10 adults. It is in danger of extinction .
This species is diurnal, measures around 5 centimeters and can be found on the Pacific coast and the Amazon in the area of Colombia. As a carnivorous species, the golden frog feeds on insects such as flies, ants, crickets, beetles, and termites. Finally, although its characteristic color is yellow, depending on the specimen the colors can vary between yellow, orange or mint green.
2. Blue arrow frog
The blue arrow frog is a color rarely seen in the animal kingdom. It is another of the specimens of poisonous frogs. However, such a bright and showy color, as in the rest of the cases, serves to alert predators of its high toxicity. It lives in tropical forests of Brazil and southern Suriname , it measures around 3 to 4 cm. and it is a diurnal species.
Regarding its diet, the blue arrow frog follows a carnivorous diet based mainly on insects. Finally, it should be noted that it is a kind of aggressive and territorial character . It is considered a minor concern.
3. Harlequin frog
The harlequin frog has a highly powerful poison, as its colors indicate, which vary between yellow, green, red and orange. Many frogs in the family also have spots or stripes. the harlequin frog is endemic to Costa Rica and western Panama, and can be seen in lowlands and humid mountain forests . This species is in critical danger of extinction due to the deforestation of its habitat and invasive species that threaten its survival.