Within the class of amphibians, we find the order Anura. It comprises about 6,500 species that are distributed on all continents, except Antarctica. Although they have greatly diversified, most of these animals depend on the presence of water for their survival, so they tend to live in humid places.
Traditionally, anurans have been divided into frogs and toads, although it has no taxonomic value. Anurans with a robust appearance, warty skin and terrestrial behavior are often called toads. The animals known as frogs, however, are usually more agile and adept jumpers. In addition, they have a more aquatic life or arboreal behavior. Do you want to know these amphibians better? Don't miss this article on our site about the characteristics of frogs
Main Characteristics of Frogs
Frogs are part of the order Anura, the most diverse of all types of amphibians. All anurans have a series of characteristics that differentiate them from salamanders, newts and caecilians. These are the main characteristics of frogs:
- Tailless: The term anuro means “without tail”. This is because, unlike salamanders and newts, their larvae or tadpoles lose their tails during metamorphosis. Therefore, adults lack it.
- Long hind legs: Frogs have longer hind legs than their front legs.
- Jumping movement: thanks to their strong hind legs, they move jumping.
- External fertilization: during sexual mating, the female lays her eggs little by little and, meanwhile, the male fertilizes them. Unlike other amphibians, the male does not introduce a copulatory organ inside the female.
- Nuptial song: the males emit a song characteristic of their species. They do this during the breeding season to attract females.
In addition to these characteristics, frogs share many other similarities with other amphibians. If you want to know them, we recommend this other article on Characteristics of amphibians.
Characteristics of frogs for kids
Frogs are very small animals that usually fit in the palm of your hand. They spend the day sunbathing right next to the water, where they swim from time to time. They need to get wet because they have very sensitive skin and use it to breathe, although they also have a nose and lungs. In addition, they have very bulging eyes, but they do not have ears.
When spring comes, the male and female meet. Together they lay their eggs in the water. As with chicks, the eggs hatch over time. Many larvae come out of them, which are called tadpoles. They don't look much like their parents, but rather are much smaller and don't have legs. They have a very large head and a tail similar to that of a fish They use it to swim, since they spend all day in the water.
Tadpoles spend most of their time eating so they can grow very quickly. As their size increases, their legs grow. The ones at the back come out first, which are the longest. Later, the front ones begin to form, a little shorter. Thanks to their new legs they begin to jump and can get out of the water. Finally, their tails disappear and they become adults, like their parents. This transformation is called metamorphosis and is very similar to what happens in butterflies.
To better understand this metamorphosis, below we show the life cycle of frogs.
Where do frogs live?
As occurs in all amphibians, the life cycle of frogs depends entirely on the aquatic environment. This is because their eggs are not isolated from the environment, as is the case in amniotic animals. In addition, their larvae are aquatic and breathe through gills, like fish. For this reason, these animals live near water sources It is one of the main characteristics of frogs, although it is not always fulfilled.
Most frogs live in places with stagnant water or slow-moving currents. Among its habitats we find the rivers and all kinds of wetlands, including lagoons, reservoirs or temporary puddles. However, many species of frogs do not live near water when they are adults, but only come to it to reproduce. Even so, they always live in humid places, since adults usually have skin respiration, so they need to have their skin always moist.
Many land frogs live in rain forests with high humidity. This is the case of tree frogs. Others choose to live in the litter that accumulates on the deciduous forest floor or remain buried in the mud during the dry season. Some frogs and toads also have lungs, making it easier for them to survive in arid places. However, frogs are much more abundant in the tropics and subtropics, since they need moderate temperatures due to their very thin and sensitive skin.
Frog feeding
Frogs feed on insects, centipedes, spiders, earthworms, snails, etc. To do this, they remain quiet near stagnant waters or in areas with high humidity, where the named animals are very abundant. When an invertebrate approaches, the frog detects its movement and quickly sticks out its extendible tongue. If successful, the invertebrate sticks to the tongue, which is coated with a slimy substance. Then it sticks its tongue back into its mouth and swallows its prey.
Some frogs have very small teeth on their upper jaws to keep prey from escaping. Only one species, the marsupial tree frog (Gastrotheca guentheri), has teeth on its lower jaw. The escuerzos (Ceratophrydae) also have a kind of fangs or spikes on the lower jaw, although they are not considered true teeth. They are one of the few frogs that use their "teeth" to catch their prey. In fact, they can consume small reptiles, amphibians and even mammals.
As for tadpoles or larvae, most are herbivoresand feed on algae. To scrape and chew these algae, they have tooth-like structures known as horny jaws. As metamorphosis proceeds, tadpoles begin to introduce some animal matter into their diet, such as dipteran larvae or mayflies. In this way, they gradually become carnivorous.
How do frogs reproduce?
Frog reproduction begins with males courting females. To get the attention of females, male frogs engage in croaking or singing throughout the breeding seasonWhen a male gets his target, he mounts above the female and holds her with her front legs. Depending on the posture they adopt, this coupling or amplexus can be of different types and depends on the species.
The amplexus can last from a few minutes to several days. During it, copulation does not take place, but the female gradually releases the eggs while the male fertilizes them. Therefore, Fertilization occurs outside the female In many species, the eggs are laid in large floating masses or attached to vegetation. In other frogs, the males carry and protect the eggs until they hatch.
The birth of frogs
When the eggs hatch, they hatch into larvae known as tadpoles These protorans are made up of a distinct head, a small body and a swimming tail. As we indicated before, they are aquatic animals that breathe through gills. Little by little, these tadpoles grow and acquire the characteristics of adult frogs. During this process, known as metamorphosis, the legs appear and the tail disappears.
In some frogs there is no larval stage, but they have a direct development. This is the case of the species of the genus Eleutherodactylus, some American frogs that mate and lay eggs on land. When these hatch, very small and independent froglets come out directly from the water masses.
Types of frogs
One of the main characteristics of frogs is their enormous diversity. These small animals have adapted to live in very different ecosystems, including islands and very remote places. For this reason, there are many types of frogs, so we are going to focus on some of the most abundant or well-known families within the Spanish-speaking world.
Typical frogs (Ranidae)
The Ranidae family is the best known group of all types of frogs, so much so that they are known as “true frogs”. It is due to its abundance and its enormous distribution, which includes almost the entire globe. However, there are only about 350 species. All of them perfectly meet the typical characteristics of frogs. For example, they present green or brown colors (with some exceptions), which helps them to camouflage themselves very efficiently.
Some examples of typical frogs are:
- Iberian Green Frog (Pelophylax perezi).
- Country Frog (Rana arvalis).
- Leopard Frog (Lithobates berlandieri).
In the image below, we can see an example of Iberian green frog.
Frogs (Hylidae)
The frog family is the most diverse group within the Anurans, with some 1,000 known species. They are distributed mainly in the tropical region of America, although they are also found in Asia and Europe. These anurans are very similar to each other and are characterized by having a small size, smooth skin and wide fingers. Some sticky discs appear on these, which gives them a great ability to climb.
Among the most outstanding species of this type of frog we find the following:
- European St. Anton Frog (Hyla arborea).
- Grey Tree Frog (Hyla versicolor).
- Boana boans (Hypsiboas boa ns).
In the following image we can see an example of European St. Anthony Frog.
Arrowhead Frogs (Dendrobatidae)
The family of arrowhead frogs includes some of the most poisonous species of frogs that exist This is why they have striking colors, which serve to inform their possible predators about how dangerous it would be to eat them. Others, however, have muted colors that blend in with the environment. These characteristics give them an evolutionary advantage, which is why they are relatively abundant in the Neotropics or tropical zone of America.
Among the dendrobatids we can find more than 200 species. The best known are:
- Golden dart frog (Phyllobates terribilis).
- Red and Blue Arrow Frog (Oophaga pumilio).
- Mining Toad (Dendrobates leucomelas).
Below is an example of golden dart frog.
Pacman Frogs (Ceratophryidae)
The escuerzos are a family of frogs that contains only about 12 South American species. However, they are very interesting amphibians. The main characteristics of the Pacman frogs are a robust body and a large and strong jaw In addition, they have some particularly bulging eyes, which reach their maximum in the escuerzo de agua (Lepidobatrachus laevis).
Another well-known Pacman frog is the common scorpion frog (Ceratophrys ornata), which lives in Argentina. This species and its similars stand out for having protuberances on the top of their heads. They are located just above the eyes, like eyebrows. This feature allows them to keep their eyes out of the mud in which they remain buried while waiting for their prey.
In the following image we can see a escuerzo de agua.
Claw or Pipe Frogs (Pipidae)
The Pipidae family comprises only about 40 species of frogs Most are distributed in sub-Saharan Africa, where they are known as nail frogs. Other species live in the tropical region of South America, where they are called pipas or Surinam toads.
The main characteristics of clawed frogs are the absence of a tongue and the dorsal position of the eyes. In addition, they have a very flattened body, which reaches its maximum in the Surinam toad (Pipa pipa). They are very generalist animals that can adapt very well to any aquatic environment. Due to their use as pets and experimental animals, some of them have become invasive species in many parts of the world. This is the case of the African clawed frog (Xenopus laevis).
In the following image we can see an example of African Clawed Frog.
