Frog

Many Anurans readily hybridise. Australia still does not have a R rating for videogames like it does for movies. The distinction is far from universally accepted, especially because there are few features that are as unique to any group as taxonomists would like. Lacking a suitable R18+ rating (the highest rating being MA15+), the game was "Refused Classification" and banned for sale because it was felt that the game was unsuitable for an audience older than 15, but younger than 18. This classification is based on the perceived possession of derived features of the three groups and refers to a fairly deep phylogenetic split, with the newest group, the Neobatrachia, having some 5,000 species. A key reason why this course of action was taken was that Rockstar did not submit GTA III to the Office of Film and Literature Classification (OFLC), the body that, among other things, rates videogames according to their content in Australia. Frogs and toads are broadly classified into three suborders: Archaeobatrachia, Mesobatrachia and Neobatrachia - respectively, old, intermediate and new frogs. After its initial release in Australia, the game was banned—the only country to do so—and a censored version of the game was released in its place.

While its skin is slightly warty, it prefers a watery habitat. It was because of GTA III that the Wal-Mart chain of retail stores announced that, for games rated "M" by the ESRB, its stores would begin checking the identification of purchasers who appeared to be under 17. An exception can be made for the Fire-bellied toad (Bombina bombina). Several minors arrested for car theft in the United States claimed their motivation was derived from playing the game. The distinction between frogs and toads is usually based on the ability to retain moisture; frogs are smooth and moist skinned, while toads have dry, warty skin. Various critics hypothesized that if children were to play the game, they might acquire sociopathic attitudes toward others. However, many families, and even genera, have a mixture of frogs and toads, so there is no taxonomic justification. In addition, all in-game crimes incurs the wrath of the police, and it is also possible to play without committing the aforementioned criminal acts.

Most frogs in the Ranidae family (true frogs) and Hylidae family (tree frogs) are considered frogs, whereas all those within the Bufonidae family (true toads) are considered toads. This action, while permitted ("sex" restores the player's health, up to 125% of its normal maximum), is never actually required. This distinction has no scientific basis, and only refers to the common name of a species. The player is rewarded with cash for various illegal and immoral actions: one allegation, frequently cited in the press, was that in the game, players had to carjack a car, pick up a prostitute, have (implied) sex with the prostitute, and then kill her and steal her money. A problem commonly associated with Anurans is the distinction between frogs and toads. For examples of video game violence, many TV news channels often show a play session of GTA III where the main character is gunning down pedestrians and blowing up police cars. The order Anura contains some 5250 species in 33 families, whereof the Leptodactylidae (1100 spp.), Hylidae (800 spp.) and Ranidae (750 spp.) are the most speciose. GTA III is controversial because of its violent and sexual content, and it generated moral panic upon its release.

Although habitat loss is certainly one of the most important features of most declines; pollutants, climate change, introduction of non-indigenous predators/competitors, and infectious diseases (see Chytrid fungus) have also been implicated. Despite its roughness and glitches, the game featured a world draw distance that was unparalleled at the time, and an overall sense of ambience and immersion that many other developers have tried and failed to emulate, even years later. The decline in frog diversity may also be to do with particular species having specialised on particular kinds of prey, such as certain kinds of earthworms that are themselves indicator species due to their close dependence on soil chemistry. Also, it was widely believed that GTA III lacked the vast development resources of its sequels, since it was considered a risky gamble at the time. Many environmental scientists feel that amphibians, and frogs in particular, may be excellent biological indicators of ecosystem function because of their location on the food web, their permeable skins and their typically bi-phasic life (in both water and on land). Part of GTA III's technical problems was due to the need to accomodate the relatively underpowered PlayStation 2 (compared to the Xbox, PC and even Dreamcast in certain respects). In many parts of the world, the frog populations have declined drastically since the 1950s. There were also serious recurring problems such as clipping (when characters and objects get "half-stuck" in walls and the ground), a bug which caused vehicles to disappear, relatively poor AI for NPCs; many of these issues were not fixed in Grand Theft Auto: Vice City.

Frogs are found nearly worldwide, but they do not occur in Antarctica and are not present on many oceanic islands. Such graphics are similar on the level of Half-Life and subpar to Quake III, but this was rarely criticized and GTA III routinely received higher graphics scores than other smaller-scaled yet better-looking games. Darwin's Frog (Rhinoderma darwinii) from Chile puts the tadpoles in its vocal sac for development. One example were the "ugliness" and simplicity of GTA III characters and objects which became especially noticeable if the main character was walking around instead of driving. To do this, the Gastric-brooding Frog must stop secreting stomach acid and suppress peristalsis (contractions of the stomach). While GTA III's sequels undoubted improved on many aspects of gameplay, many technical gliches were also carried over. The female Gastric-brooding Frogs (genus: Rheobatrachus) from Australia swallows its tadpoles which develop in the stomach. Alternatively, many reviewers were biased in favour of the GTA series.

The tadpoles will reside in the pouch until the end of metamorphosis. In other words, GTA III and especially subsequent GTA games following the GTA III formula were so sure to be critically acclaimed blockbusters that they were not seriously scrutinized (most flaws were downplayed) during early reviews. The male Australian pouched frog (Assa darlingtoni) has pouches along its side. Aside from its violence (see #Controversy), there was criticism, often for the "lack of criticism" that surrounded the Grand Theft Auto series after the launch of Grand Theft Auto III. Many frogs protect their offspring inside their own body. [1], [2]. the midwife toads, Alytes spp.). The game was touted as revolutionary by several game review websites and publications, and received such rewards as Game of the Year from GameSpot, GameSpy, and Cheat Code Central, and Best Action Game of 2001 by IGN, receiving an average of about 95% from the review websites and publications.

Other frogs will carry the eggs and tadpoles on their hind legs or back (e.g. All subsequent games in the series have followed the GTA III formula and have been best-selling and critically-acclaimed (and controversial) as a result. The parent will then feed it through laying unfertilised eggs into the bromeliad, until the young have metamorphosed. As a result of these shrewd moves, the Grand Theft Auto series was now a blockbuster franchise. After hatching, a parent (sex depending upon the species) will move them, on its back, to a water-holding bromeliad. Also notable is that GTA III was the first in the series to be released on video game consoles before the PC, citing the growing size of the console market. The frog will urinate if they become too dry. Although multiplayer was discarded, it had a minimal impact as the many major improvements won legions of fans over to a series which formerly enjoyed a cult following.

This protection involves guarding the eggs from predation, and keeping the eggs moist. All of this is seemlessly integrated in the realistic setting of a (dysfunctional) urban environment which parodies a real-life city. Some species of poison dart frogs will lay eggs on the forest floor, and protect them until hatching. Grand Theft Auto III was the first game in the series to feature a deep storyline with high quality voice acting and navigable three-dimensional graphics. Although brood care is much less common, there is a great diversity of such behaviours. The Double Pack's success for Xbox was due to several factors, the critical acclaim (not just for the GTA series but also for the Xbox improvements) and controversial game content, two games in one, graphical improvements, and lastly the Double Pack debuted at half the price of a regular Xbox game. This reduces the number of predators, and therefore increases the number of surviving offspring. GTA III continued to sell well as part of the Xbox Double Pack, even though it was two years old when the Double Pack hit shelves in December 2003.

They will lay the eggs en masse, and any predator within the region will die once they eat the egg or tadpole. This was a remarkable achievement in an industry where most games experience strong drops in sales despite price drops, as gamers have a strong tendency to purchase only the "next new thing". Although the Cane Toad, and similar species, do not advertise their toxicity the offspring still survive in large numbers. Later discounted to $19.95 as part of Sony's "Greatest Hits" program, it continued to sell well and went on to become the second best-selling video game of 2002, behind only the next game in the series, 2002's Vice City. Other poisonous species will not, such as the Cane Toad (Bufo marinus). Upon its release, GTA III unexpectedly emerged as a smash hit at its initial US$49.95 price and became the #1 selling video game of 2001 in the United States. Some tadpoles will advertise their toxicity, usually poison dart frogs, to warn potential prey. Grand Theft Auto: Liberty City Stories (2005) was released for the PlayStation Portable, also set in the same location as GTA III, but taking place in 1998, three years before the events in GTA III.

Poisonous tadpoles and/or eggs is an adaptation also present in frogs. Grand Theft Auto Advance (2004) was initially intended as a Game Boy Advance port of GTA III, but has since introduced a new storyline set in Liberty City, roughly one year before the events in GTA III. The tadpoles drop into the water upon hatching. Two handheld titles based on GTA III have also been released. One way in which some species avoid the predation and pathogens eggs are exposed to in ponds is to lay eggs on leaves above the pond, with a coating designed to retain moisture. The Double Pack was not released for PC. However, there is a greater chance some will survive than a laying of smaller numbers. The Xbox version of the Double Pack has improved audio, polygon models, and reflections over the PC and PS2 versions of the game.

A majority of the offspring will usually die due to predation, disease or competition with other tadpoles. However, the agreement was amended in 2003 and the Grand Theft Auto: Double Pack containing both GTA III and Vice City was released for PS2 and Xbox in December 2003. The female will lay thousands of eggs in one laying. The Xbox version was initially supposed to be released in spring 2002 but it was shelved when Sony signed an agreement with Take-Two Interactive (Rockstar Games' parent company), making the GTA series a PlayStation 2 exclusive until November 2004. The most common adaptation is mass laying of eggs. The PC version does, however, support higher resolution textures and a custom option for MP3s playback in cars. Frogs have evolved many techniques to protect the survival of the next generation. This was due to technical issues; the game engine rendered everything within the draw distance, even things hidden behind buildings or trees, whereas Vice City only rendered what could actually be seen.

The egg and tadpole stage of a frog's life cycle is usually the most dangerous due to easy predation. The PC version of the game, released on May 21, 2002, has been criticized for performance problems, especially in light of the much smoother performance of the next game in the GTA series, Vice City. More importantly, reproducing early in the season ensures that appropriate food is available to the developing frogs at the right time. The list of Grand Theft Auto III radio stations is as followed:. Reproducing in these conditions helps the developing tadpoles because dissolved oxygen concentrations in the water are highest at cold temperatures. The radio ads also gave out their official phone numbers which were also (apparently) registered by Rockstar; however in this case curious gamers only found an answer phone at the other end. Water temperatures at this time of year are relatively low and typically between four and 10 degrees Celsius. However, although looking very much like genuine online stores, all links to purchase or order the products actually led to Rockstargames.com.

In the UK most common frog populations produce frogspawn in February although there is wide variation in timing. All of these sites actually existed; they were set up to tie in with the game. Most temperate species of frog reproduce in the period between late autumn to early spring. These ads often referred to their advertisers' official websites, such as Petsovernight.com. The eggs will hatch after a short time, releasing tadpoles. Each station featured various commercials at intervals. The eggs are typically brown or black, with a clear, gelatine-like, covering. One of the stations was a full-length talk show, and many of the callers were actually characters from the story missions, often demonstrating the same views and eccentricities that had become apparent to the player during the missions.

Once the eggs come in contact with the water, they will swell, and form a protective coating. Much of the music was specially written for the game (as well as many songs originating from the first two GTAs), however the Xbox and PC ports allowed the player to use their own MP3s, and later games included actual, licenced music. The female then releases her eggs, which the male frog covers with a sperm solution before the eggs make contact with the water. One of the game's subtler inclusions was a variety of radio stations (part of the official soundtrack). This involves the male mounting the female and gripping her tightly. Some of these features, notably monetary awards and the top-down view, would eventually be removed in following GTA titles. The male and female frog, will then undergo amplexus. These included monetary awards for crashing onto cars, blowing up vehicles, and killing pedestrians (although the last feature would require that the player pick up the money dropped by dead pedestrians on foot), a crusher, vehicle import-exports, train services, and an optional top-down camera view synonymous in the game's previous installments.

Some species have satellite males who do not call but intercept females approaching one of the calling males. As a direct descendent to Grand Theft Auto and Grand Theft Auto 2, Grand Theft Auto III retained several features that were common in the previous two titles. The call is unique to the species, and will attract females of that species. Pedestrians sometimes get into fights, and car accidents between non-player vehicles may occur on their own, without any player interference to trigger these events. They will then call, collectively becoming a chorus of frogs. The game is also noted for the emergent behavior of its non-player characters. The life cycle continues with male frogs of a species assembling at a still water source. Law enforcement and members of rival gangs can be attacked and will respond with weapons of their own.

The French custom of eating frog legs is the source of the English use of the derogatory nickname "frogs" for French people. Citizens can be beaten up, robbed, run over, or shot, allowing the player to extract money and/or weapons. Frog legs are a delicacy in China, France, and in many parts of the American South, especially Louisiana. Cars can be smashed or stolen; carjacking was often required if the player doesn't have (or had lost) their own vehicle and was required to travel quickly. Frogs are also eaten by people. Passing vehicles and pedestrians are not just cosmetic "flavor" for the environment, but are actually part of game play. Frogs are themselves predated by birds, large fish, snakes, otters, foxes, badgers, coatis, and other animals. The game is remarkable in its depiction of what seems to be a very large city with things happening all the time in different neighborhoods.

Some frogs use their sticky tongues effectively in catching fast-moving prey, while others capture their prey, and force it into their mouth with their hands. Thanks to the strikingly open-ended game design, it is quite possible—and common—for players to ignore the main missions and play the side missions, or simply cruise around enjoying Liberty City's sights. A few of the larger species may eat larger prey, such as small mammals, fish and smaller frogs. As the player completes missions for different gangs, rival gang members will come to recognize the character and subsequently shoot on sight (if armed). All juvenile and adult frogs are carnivores, eating invertebrates such as insects, worms and spiders. Similarly, the player's place within the story will affect his view in the "eyes" of non-playable characters. Most species complete their development within about three months, while others, such as the midwife toad Alytes obstetricans and the Common Spadefoot (Pelobates fuscus), hibernate as tadpoles and complete their development the following spring. However, the nature of the game does demand some limits to the player's freedom: just as new areas become open, some will be permanently denied of access once the player fulfills their purpose.

The final stage of development from froglet to adult frog involves apoptosis (programmed cell death) of the tail. As can be expected from a video game with a linear plot, new neighborhoods and districts in Liberty City will become open to the player's exploration as missions are completed and the game's story unfolds. As tadpoles grow, they undergo metamorphosis, in which they develop legs and lungs, have their intestines shorten to accommodate a carnivorous diet, to become a froglet. Police and Fire Fighter missions are similarly available. Cannibalism has also been observed among tadpoles. If the player acquires a taxi cab, he can pick up designated non-player characters as fares and drop them off at different parts of the city for a cash payment; carjacking an ambulance lets the player pick up injured NPCs and drive them to the hospital for a cash reward. Tadpoles are entirely aquatic, and are vulnerable to predation by fish, newts, predatory diving beetles, and birds such as kingfishers. Alternately, he may choose to drive around the city, stealing cars, running over pedestrians, and avoiding (or opposing) the police.

Some species are carnivorous at the tadpole stage, usually eating small larvae and fish. He is able to go on missions (shaking down a local business for "protection money", clearing the streets of drug dealers, or assassinating leaders of rival gangs, for example) in order to advance in the ranks of his current gang. Tadpoles are typically herbivorous, feeding mostly on algae, including diatoms that are filtered from the water through the gills. The player's character has a degree of freedom in his actions that, although being heavily inspired by Rockstar North's (then DMA Design) earlier Nintendo 64 game Body Harvest, was groundbreaking in 2001 and has arguably been only surpassed by the game's sequels. Frogs start life as tadpoles. However, if the main character attacks pedestrians or gang members, the cop will give chase. The life cycle of frogs contains two main stages, the adult and the tadpole. If the main character is attacked by pedestrians or gang members, a patrolling cop will ignore the offending attackers.

Edible frogs rely on skin modifications rather than poisons for protection. The police AI follows a double-standard. There is also one nonpoisonous frog in South America which mimics a poisonous frog’s colors to protect itself. Unfortunately, completing certain missions inevitably causes the player to gain the attention of local police enforcement. Poisonous frogs tend to advertise their toxicity with bright colours. The only way to get rid of wanted levels is to pick up police-bribes or repaint the car the player is driving at the three local Pay 'N' Sprays. The name of the frog was changed from Poison Arrow Frog to Poison Dart Frog in the early 1980's. Gunning down pedestrians and destroying cars will further raise the wanted level (the maximum level is six stars) and eventually bring increasingly stronger police enforcement in the form of SWAT teams, FBI agents, and the National Guard.

It was previously a misconception that the poison was placed on arrows rather than darts. Cops will chase after the player by foot and car but will do little else. Some natives of the Amazon area extract poison from the Poison Dart Frog and put it on their darts when hunting. Minor infractions such as carjacking or fist assaults will cause a one-star wanted level. The Australian Corroboree Frogs, Pseudophryne corroboree and Pseudophryne pengilleyi, have been discovered to be able to manufacture an alkaloid not derived from their diet ^[2]. Any type of infractions will raise the player's wanted level and thus cause the police to give chase. Generally the frog obtains the poison from the insects and other animals it eats. The Liberty City Police Department (LCPD) is the city's police agency.

Many predators of frogs have adapted to tolerate high levels of these poisons, whereas others, including humans, may be severely affected and hence deterred by them. These risk-reward balances give the game more subtlety than the nature of the in-game actions would suggest. The chemical makeup of these toxins varies from irritants to hallucinogens, convulsants, nerve poisons, and vasoconstrictors (which act to narrow the blood vessels). However, attempting to car-jack a Mafia vehicle often results in pursuit by the former occupant (who is invariably armed). Some frogs, such as the arrow-poison frog, are especially toxic. Each car has its own particular performance characteristics; for instance, a "Mafia Sentinel" car is much faster and able to corner much better than a minivan. All frogs have poison glands in their skin. The principal activity in the game is carjacking: the player may walk up to the side of a passing car and press a single button to yank the driver out of the car, get in, and start driving.

Certain frogs change colour between night and day, which is caused by light and moisture stimulating the pigment cells and causing them to expand or contract. He then takes on work as a local thug and rises in power as he works for multiple rival crime gangs. Arboreal frogs will usually have smooth skin to effectively disguise them as leaves. While he is being transferred, an attack on the police convoy sets him free. Features such as warts or skin folds are usually found on ground dwelling frogs, where a smooth skin would not disguise them effectively. He is double-crossed by his partner/girlfriend, Catalina, during a bank robbery and sent to jail. For example, White's tree frog (Litoria caerulea) varies in shades of green and brown. He received the name "Claude" in a brief cameo in the series' later game Grand Theft Auto: San Andreas; because of this name he is theorized to be "Claude Speed" from GTA2).

However, this is usually restricted to shades of one or two colours. Black". Some frogs have the ability to change colour. Throughout the story, the main character is never named (though he is referred to in the fan community variously as "Fido", "The Kid", or "Mr. Nocturnal frogs will usually find the ideal camouflaged position during the day to sleep. The game takes place in Liberty City, a fictional city on the East Coast (based on New York City). Most camouflaged frogs are nocturnal, which adds to their ability to hide. .

Camouflage is a common defensive mechanism in frogs. It is the third in the Grand Theft Auto series and was the #1 selling game of 2001. They can also breathe with their mouths closed by taking air in through the nostrils (causing the throat to puff out), and then compressing the floor of the mouth, which forces the air into the lungs. Grand Theft Auto III, or GTA III, is a video game developed by DMA Design, published by Rockstar Games in October 2001 for the PlayStation 2 video game console, May 2002 for Windows-based PCs, and in November 2003 for the Xbox video game console. Frogs can breathe by simply opening their mouth and letting air flow into their windpipe. Grenades (Slot 12). Their lungs are similar to those of humans, but the chest muscles are not involved in respiration and there are no ribs or diaphragm to support breathing. Molotov cocktails (Slot 11).

Adult frogs use their lungs when on land. Flamethrower (Slot 10). When a frog is underwater, oxygen is transmitted through the skin directly into the bloodstream. Rocket launcher (Slot 9). There are a number of blood vessels near the skin. Sniper rifle (Slot 8). The skin of amphibians is moistened by secretions of mucus, and is used for respiration at times. M-16 (Slot 7).

Just as frogs are able to absorb water through their skin, they are also able to breathe through their skin. AK-47 (Slot 6). The egg and tadpole development is very fast in comparison to most frogs, to prevent the pond drying before metamorphosis. Shotgun (Slot 5). Once it rains, they will emerge, find a temporary pond and breed. Uzi (Slot 4). The Australia genus Cyclorana, and American genus Pternohyla will dig underground, form a water impervious cocoon and hibernate during dry periods. Pistol (Slot 3).

For this reason, for frogs to survive in deserts or drought prone regions, where water may not be accessible for many years, other adaptations must suffice. Baseball bat (Slot 2). These adaptations only reduce water loss enough for a predominately arboreal existence, and are not suitable for arid conditions. Fist (Slot 1). This position involves the frog lying with its toes and fingers tucked under its body and chin respectively, with no gap between the body and substrate. Chatterbox FM. This includes nocturnal activity, and resting in a water conserving position. Flashback 95.6.

Some species will use behavioural traits to reduce water loss. MSX FM. Some tree frogs reduce water loss with a water proof layer of skin. Game Radio FM. Many frogs, such as tree frogs, have behaviourally and physiologically adapted to conserving water. Lips 106. However, the permeability of frog's skin also results in some frogs losing large amounts of water. Rise FM.

Many frogs are able to absorb water directly through their skin, especially through the pelvic area. K-Jah. The croak of the American bullfrog (Rana catesbiana) is sometimes spelt "jug o' rum". Double Cleff FM. This difference is due to the different species within each region (for example, Common frog (Rana temporaria) in Britain and Leopard frog (Rana pipiens) in the USA). Head Radio. Frog noise tends to be spelt (for English speakers) as "crrrrk" in Britain and "ribbit" in the USA.

Many species of frog have deep calls, or croaks. The effectiveness of the call is unknown, however it is suspected the call intrigues the predator, until another animal is attracted, distracting them enough for its escape. This is done with the mouth open, and usually results in a higher pitched call. A distress call is emitted by some frogs when they are in a position of danger.

All of these calls are emitted with the mouth of the frog closed. Many species also have a territorial call that is used to chase away other males. A male frog will emit a different call when mounted by another male. Polypedates leucomystax, produce a call reciprocal to the male's which acts as the catalyst for the enhancement of reproductive activity in the breeding colony (Roy, 1997).

Females of many frog species, e.g. Males will either call in a group, called a chorus, or individually. The main reason for calling is for the male to attract a mate. The flowing water overpowers any call, and they must communicate by other means.

Species of frog which have lost a vocal sack, and do not have a loud call, tend to inhabit areas close to flowing water. Their buccal cavity is enlarged and dome shaped, acting as a resonance chamber, and amplifies their call. Some frogs which lack vocal sacks, such as the frogs from the genera Heleioporus and Neobatrachus, can still have a loud call. Each call is unique to a species.

The vocal sac is a membrane of skin under the throat or on the corner of the mouth which distends during the amplification of the call. In most calling frogs, the sound is amplified by the vocal sac(s). It will call by passing air through the larynx, in the throat. The males of most species of frogs will call for a variety of reasons.

The hind legs of ground dwelling frogs are better suited to hopping. Ground dwelling frogs will usually have reduced toe pads (if any at all), and webbing. Ground dwelling frogs do not have much in the way of specific adaptations, except they lack the adaptations of aquatic and arboreal frogs. Therefore, many arboreal frogs have hips which allow both hopping and walking.

Transport through trees can be dangerous just through the process of hopping. This aids in creating the greatest surface area touching the substrate, by applying even pressure to the toes/fingers. Tree frogs also have a small structure called the intercalory structure in their toes and fingers. ^[1].

For this reason, wet frogs cannot grip to smooth surfaces. Capillarity then maintains the grip . On smooth surfaces, the gaps drain away excess moisture, to produce a thin layer of moisture. The pressure from the frog interlocks any irregularities on a surface, and therefore grips the surface.

The cells on the pads are interlocking, with gaps between each cell. The toe discs do not work by suction, but a more complicated system. Arboreal frogs have toe pads on the end of their toes to help grip. For example, the African dwarf frog (Hymenochirus sp.) is completely aquatic and its hands are fully webbed, whereas White's tree frog is arboreal, and is only half or one quarter webbed.

The degree to which a frog is aquatic, can usually be predicted from the amount their hands/feet are webbed. To do this, frogs have evolved a structure similar to most semi-aquatic animals - webbed feet and hands. An aquatic lifestyle for a frog requires a frog to move fast through the water. The three main habitats are terrestrial, aquatic and arboreal.

This is due to the large variety of habitats in which frogs inhabit. The feet/hands and legs of frogs, are one of the most varied structures within the order Anura. Hence, dead frogs are often used for dissections in high school and university anatomy classes, often after being injected with coloured plastics to enhance the contrast between different organs. The internal organs of frogs are relatively odourless.

They have a tympanum on each side of their head, which is involved in hearing, and is covered by skin in some species. Frogs have three eyelid membranes: one transparent to protect the eyes underwater, and two which are translucent to opaque. The skin lacks keratin and hangs loosely on the body because of the lack of loose connective tissue, and can be smooth, warty or have skin folds. Frogs range in size from 10mm (Psyllophryne didactyla of Brazil and Eleutherodactylus iberia of Cuba) to 300mm (Goliath frog, Conraua goliath, of Cameroon).

They have a short vertebral column, with no more than ten free vertebrae, followed by a fused tail bone, usually resulting in a frog without a tail. Frogs are generally well suited to jumping, and have long hind legs, with elongated ankle bones. However, there are some general characteristics that distinguish them from other amphibians. Because of the great diversity of frogs (approximately 5250 described species), many characteristics are not shared by all of the species.

. Their distribution ranges from tropic to subarctic regions, with most of the approximately 5250 described species found in tropical rainforest. Some frogs are poisonous and have warning colouration; others are well camouflaged. Most frogs have a semi-aquatic lifestyle, and their larvae, called tadpoles, have gills and develop in water.

"True frogs" are of the family Ranidae. The only family exclusively given the common name "toad" is Bufonidae, but many species from various other families are also called "toads". A distinction based on appearance is often made between frogs and toads, but this has no scientific basis. Adult frogs are characterised by long hindlegs, a short body, webbed digits, protruding eyes and the absence of a tail.

Frog is the common name for amphibians in the order Anura.