''Hoplobatrachus tigerinus'', commonly known as the Indian bullfrog, is a large species of
fork-tongued frog found in
South
South is one of the cardinal directions or Points of the compass, compass points. The direction is the opposite of north and is perpendicular to both east and west.
Etymology
The word ''south'' comes from Old English ''sūþ'', from earlier Pro ...
and
Southeast Asia
Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia, South-eastern Asia or SEA, is the geographical United Nations geoscheme for Asia#South-eastern Asia, south-eastern region of Asia, consistin ...
. A relatively large frog, it is normally green in color, although
physiological
Physiology (; ) is the scientific study of functions and mechanisms in a living system. As a sub-discipline of biology, physiology focuses on how organisms, organ systems, individual organs, cells, and biomolecules carry out the chemical ...
traits vary between populations.
Sexual dimorphism
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...
exists between males and females. Outside of its native range, ''H. tigerinus'' is a rapidly-spreading
invasive species
An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...
. Both adults and
tadpoles
A tadpole is the larval stage in the biological life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some fish-like features that may not be found in ...
can severely damage the populations of other frog species. Typically, Indian bullfrogs dwell in
wetland
A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The ...
environments. Research has been conducted on their ability to control
mosquitos
Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning "gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "litt ...
.
Taxonomy
The Indian bullfrog was first described by François-Marie Daudin in 1802, as Rana tigerina. The type locality was given as "Bengale, India". In 1992, it was transferred to the genus ''
Hoplobatrachus
''Hoplobatrachus'' is a genus of frogs in the family Dicroglossidae. This genus is found in both Sub-Saharan Africa and southern and southeastern Asia. It is the sister taxon of ''Euphlyctis'', although there is some evidence that it might be p ...
'' by Alain Dubois, as ''Hoplobatrachus tigerinus''. In addition to various other renditions and misspellings of ''R. tigerina'', other synonyms include ''Rana picta'', ''Dicroglossus tigrinus'', and ''Euphlyctis tigerina''.
Description
The Indian bullfrog is a large species of frog. They can grow to be , with heads generally longer than they are wide, although older individuals tend to have wider heads. Normally green or brown with dark spots, males turn yellow during the breeding season. They tend to have a yellow streak along the spinal region of their back.
[
Significant variation, in both color and size, exists between different populations, even geographically close ones. A 2012 study found that frogs from different villages in the ]Jamshoro District
Jamshoro District ( sd, ضلعو ڄام شورو, ur, ), is a district of Sindh province, Pakistan. Jamshoro city is the capital while Kotri is the largest city of the Jamshoro District. The district borders Dadu district to the north. To the e ...
of Sindh
Sindh (; ; ur, , ; historically romanized as Sind) is one of the four provinces of Pakistan. Located in the southeastern region of the country, Sindh is the third-largest province of Pakistan by land area and the second-largest province ...
, Pakistan
Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...
were consistently different in size and coloration from other local populations. The study suggested that this was caused by food and water quality differences, as well as varying ages.[
Their hands are unwebbed, while their feet are essentially fully webbed. Males have ]nuptial pad
A nuptial pad (also known as thumb pad, or nuptial excrescence) is a secondary sex characteristic present on some mature male frogs and salamanders. Triggered by androgen hormones, this breeding gland (a type of mucous gland) appears as a spiked ...
s (swellings present on the forearms of certain male amphibians used to grasp females for mating) on the first finger and dual blue-colored vocal sacs on either side of the throat. The tail
The tail is the section at the rear end of certain kinds of animals’ bodies; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, r ...
and fins
A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. Fin ...
of tadpoles are speckled in black, with tail tips darkly colored.
In males, the tympanum is wider than the eye
Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...
, while in females the eye is wider than the tympanum. Females are also heavier and longer than males.
Distribution and habitat
Distribution
The Indian bullfrog is native to mainland Afghanistan
Afghanistan, officially the Islamic Emirate of Afghanistan,; prs, امارت اسلامی افغانستان is a landlocked country located at the crossroads of Central Asia and South Asia. Referred to as the Heart of Asia, it is bordere ...
, Bangladesh
Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mos ...
, India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
, Myanmar
Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John C. Wells, Joh ...
, Nepal
Nepal (; ne, नेपाल ), formerly the Federal Democratic Republic of Nepal ( ne,
सङ्घीय लोकतान्त्रिक गणतन्त्र नेपाल ), is a landlocked country in South Asia. It is mai ...
, and Pakistan
Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...
, as well as possibly Bhutan
Bhutan (; dz, འབྲུག་ཡུལ་, Druk Yul ), officially the Kingdom of Bhutan,), is a landlocked country in South Asia. It is situated in the Eastern Himalayas, between China in the north and India in the south. A mountainous ...
and China
China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...
, although its presence is uncertain. It has been introduced to Maldives
Maldives (, ; dv, ދިވެހިރާއްޖެ, translit=Dhivehi Raajje, ), officially the Republic of Maldives ( dv, ދިވެހިރާއްޖޭގެ ޖުމްހޫރިއްޔާ, translit=Dhivehi Raajjeyge Jumhooriyyaa, label=none, ), is an archipelag ...
, Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
, and India's Andaman Islands
The Andaman Islands () are an archipelago in the northeastern Indian Ocean about southwest off the coasts of Myanmar's Ayeyarwady Region. Together with the Nicobar Islands to their south, the Andamans serve as a maritime boundary between th ...
, where it is now a widespread invasive species
An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...
. Likely areas to be invaded in the future include the Mascarene Islands
The Mascarene Islands (, ) or Mascarenes or Mascarenhas Archipelago is a group of islands in the Indian Ocean east of Madagascar consisting of the islands belonging to the Republic of Mauritius as well as the French department of Réunion. Thei ...
, Malaysia
Malaysia ( ; ) is a country in Southeast Asia. The federation, federal constitutional monarchy consists of States and federal territories of Malaysia, thirteen states and three federal territories, separated by the South China Sea into two r ...
, Indonesia
Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Guine ...
, and East Africa
East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territories make up Eastern Africa:
Due to the historical ...
.
Andaman Islands
First reported in October of 2011, ''H. tigerinus'' has become a major threat to the fauna of the Andaman Islands. Larger than native frogs, it can easily consume large numbers of them, along with reptiles such as the Andaman worm snake
The Andaman worm snake (''Gerrhopilus andamanensis'') is a species of harmless blind snake in the family Gerrhopilidae. The species is endemic to the Andaman Islands. No subspecies are currently recognized.
Geographic range
It is found in the ...
and Andaman day gecko
The Andaman day gecko (''Phelsuma andamanensis''), also known as the Andaman Islands day gecko, is a species of gecko in the genus ''Phelsuma''. It is endemic to the Andaman Islands of India, and has recently been introduced to the Nicobar islan ...
, as well as centipedes
Centipedes (from New Latin , "hundred", and Latin , "foot") are predatory arthropods belonging to the class Chilopoda (Ancient Greek , ''kheilos'', lip, and New Latin suffix , "foot", describing the forcipules) of the subphylum Myriapoda, an a ...
. The rapid spread of this frog throughout the archipelago
An archipelago ( ), sometimes called an island group or island chain, is a chain, cluster, or collection of islands, or sometimes a sea containing a small number of scattered islands.
Examples of archipelagos include: the Indonesian Archi ...
is harmful to human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...
residents as well, having disastrous effects on the local economy. The bullfrogs frequently kill and eat residents' fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
and chicks, both of which are important to the islanders. While Indian law
The legal system of India consists of civil, common law and customary, Islamic ethics, or religious law within the legal framework inherited from the colonial era and various legislation first introduced by the British are still in effect in ...
prohibits their killing, it is still done, both out of desire to rid the islands of the species and for food (''H. tigerinus'' is a very cheap source of protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
). Despite these efforts, the frogs' spread continues.
One trait in particular that facilitates this invasion is the carnivorous nature of ''H. tigerinus'' tadpoles. Experimentation at the Andaman Nicobar Environment Team (ANET) field station on South Andaman Island
South Andaman Island is the southernmost island of the Great Andaman and is home to the majority of the population of the Andaman Islands.
It belongs to the South Andaman administrative district, part of the Indian union territory of Andaman and ...
demonstrated that when kept together in pools with adequate amounts of food, Indian bullfrogs rapidly devoured the tadpoles of native species. This behavior did not appear to increase their growth rate, the time it took to metamorphosize, or adult size. They consumed other tadpoles so quickly that no competitive behavior could be observed between different species. Even when kept only with their own kind, their aggression towards other tadpoles remained, with only three surviving per pool on average (for comparison, when kept without bullfrogs, native tadpoles—of the species ''Microhyla chakrapanii
''Microhyla chakrapanii'' is a species of frog in the family Microhylidae, the narrow-mouthed frogs. It is endemic to the Andaman Islands. It is also known as the Mayabunder rice frog, Chakrapani's narrow-mouthed frog, and bilateral banded frog. ...
'' and ''Kaloula ghoshi
''Kaloula'' is a genus of microhylid frogs found in southern and eastern Asia. They are sometimes known as the Asian narrowmouth toads.
Species
The genus currently has at least 19 species. Some sources also recognize ''Kaloula macrocephala'' Bo ...
''—lived to metamorphosis three out of four times, on average). It is likely that the frog will eventually reach the Nicobar Islands
The Nicobar Islands are an archipelagic island chain in the eastern Indian Ocean. They are located in Southeast Asia, northwest of Aceh on Sumatra, and separated from Thailand to the east by the Andaman Sea. Located southeast of the Indian s ...
.
Madagascar
The species was first introduced to Madagascar for food, for which it is still used, although it has now become a pest. Human consumption has not been enough to prevent its spread.
Habitat
''Hoplobatrachus tigerinus'' is typically found in freshwater environments, especially wetlands
A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The ...
, such as paddy fields
A paddy field is a flooded field of arable land used for growing semiaquatic crops, most notably rice and taro. It originates from the Neolithic rice-farming cultures of the Yangtze River basin in southern China, associated with pre-Aust ...
. It is not generally found in other ecosystems, such as forests
A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...
and coastal areas.
Behavior and ecology
![Hoplobatrachus tigerinus Indian bullfrog vijayanrajapuram2](https://upload.wikimedia.org/wikipedia/commons/0/0f/Hoplobatrachus_tigerinus_Indian_bullfrog_vijayanrajapuram2.jpg)
Diet
Adult Indian bullfrogs eat invertebrates
Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...
, small mammals
Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
, and birds
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
. Tadpoles are known to consume mosquito larvae, including those of the species ''Aedes aegypti
''Aedes aegypti'', the yellow fever mosquito, is a mosquito that can spread dengue fever, chikungunya, Zika fever, Mayaro and yellow fever viruses, and other disease agents. The mosquito can be recognized by black and white markings on its legs ...
'' and ''Culex quinquefasciatus
''Culex'' is a genus of mosquitoes, several species of which serve as vectors of one or more important diseases of birds, humans, and other animals. The diseases they vector include arbovirus infections such as West Nile virus, Japanese encep ...
''.
Reproduction and life cycle
''Hoplobatrachus tigerinus'' reproduce during the monsoon season
The wet season (sometimes called the Rainy season) is the time of year when most of a region's average annual rainfall occurs. It is the time of year where the majority of a country's or region's annual precipitation occurs. Generally, the sea ...
, in pools of rainwater. They produce many eggs at one time, although many tadpoles die before reaching adulthood. They can live over seven years in the wild.
Research
The Indian bullfrog has been found to be an efficient means of controlling mosquito populations. Silver nanoparticles
Silver nanoparticles are nanoparticles of silver of between 1 nm and 100 nm in size. While frequently described as being 'silver' some are composed of a large percentage of silver oxide due to their large ratio of surface to bulk silve ...
(AgNP), which are highly toxic to the larvae of ''Aedes aegypti'' (the yellow fever mosquito), were found to be able to work in conjunction with ''Hoplobatrachus tigerinus'' tadpoles to exterminate large numbers of mosquito larvae, with tadpoles consuming more AgNP exposed larvae than non-exposed ones. While AgNP did not cause any immediate harm to the tadpoles, potential long-term side effects (such as changes in life expectancy) have yet to be studied.
See also
*American bullfrog
The American bullfrog (''Lithobates catesbeianus''), often simply known as the bullfrog in Canada and the United States, is a large true frog native to eastern North America. It typically inhabits large permanent water bodies such as swamps, po ...
* Frog
A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...
References
Further reading
*Islam, M. R. and M. B. Hossain. (2012)
Genetic variation of three populations of Indian frog (''Hoplobatrachus tigerinus'') revealed by allozyme marker.
''International Journal of Zoological Research'' 8(4) 150-56.
*Kamphon Isarankura na Ayuthaya Nongyao Chanpong Phusati Pariyanonth (Chulalongkorn Univ., Bangkok (Thailand). Faculty of Science. Dept. of Biology). (1989)
General morphology and anatomy of frog (Rana tigerina).
''Thai National AGRIS Centre''.
External links
Mast cell studies; conducted on Rana tigrina.
{{Taxonbar, from=Q221745
Amphibians described in 1803
Hoplobatrachus
Amphibians of Afghanistan
Amphibians of Bangladesh
Amphibians of Myanmar
Frogs of India
Amphibians of Nepal
Amphibians of Pakistan