Indus Valley bullfrogs (Hoplobatrachus tigerinus) are found throughout the wetland areas of India, Bangladesh, and northern Pakistan. They have also been reported in southern Nepal and northern Myanmar. Additionally, there are unconfirmed reports of Indus Valley bullfrogs in Afghanistan. They have been introduced to the Maldives and Madagascar, occupying lower altitudes, mostly in northwestern regions. The altitude range of Indus Valley bullfrogs is 25 to 900 m, but a new maximum elevation of 1,140 m was recently recorded in Nepal. (Mishra, 2017; Padhye, et al., 2008)
Indus Valley bullfrogs live mostly in freshwater wetlands, both natural and artificial. They are uncommon in forested or coastal regions. They typically inhabit holes or vegetative cover near permanent water sources. (Alexander, 2011; Padhye, et al., 2008)
Indus Valley bullfrogs are large-bodied frogs with pointed snouts and sharp teeth. They weigh 0.27 to 0.77 kg and are an average of 167.6 mm in length. Indus Valley bullfrogs have dull, olive-green or brown-green coloration, which helps them camouflage with their environment. However, males become bright yellow in color with purple vocal sacs during mating season. These bright colors play a role in mate selection by females. (Mishra, 2017; Mohanty and Measey, 2018)
Indus Valley bullfrogs develop from eggs, which females lay in large clutches in their wetland habitats, often near vegetation. Tadpoles hatch from eggs and feed on insects and other tadpoles as they grow, develop, and undergo metamorphosis. However, there is limited information regarding the exact duration of egg and tadpole development. Adult Indus Valley bullfrogs exhibit indeterminate growth, meaning they do not stop growing throughout their life. They grow an average of 7.31 cm in their first year, but growth rates decrease once they reach sexual maturity and, by their third year, average growth is measured at about 0.53 cm per year. Males reach sexual maturity as early as 10 months, whereas females do not reach sexual maturity until the end of their second year. As a result, females Indus Valley bullfrogs are larger than males on average. (Islam and Belal Hossain, 2012; Mohanty and Measey, 2018)
Indus Valley bullfrog males attract females using mating calls and bright colors, which they develop at the beginning of mating season. Males turn a bright yellow color with vibrant blue vocal sacs, while females remain the dull olive color throughout the year. Males use their brightly colored vocal sacs not only to attract mates visually, but also as a means of producing a loud, shrill vocal call, which they repeat several times. Males sit close to each other in shallow water and females gather nearby. If a female approaches a male, that male mounts the female in a position called amplexus. Neighboring males often climb on top of the pair in efforts to disrupt the mating process. This normally results in fighting amongst males, and only stops when the mating pair moves to a quieter space. (Ali, 2017; Padhye, et al., 2008)
Indus Valley bullfrogs breed during the rainy season. More specifically, almost all breeding activity occurs around monsoons. Males develop bright yellow coloration during mating season and produce loud mating calls from shallow areas of water bodies to attract females. After mating with males, females produce a large number of eggs that are laid in pools of water. They often attach their eggs to vegetation or objects that sink into the water, so that their eggs are hidden from predators. Each individual egg is enclosed in a double coat of jelly and ranges from 2.5 to 2.8 mm in diameter. Indus Valley bullfrog tadpoles experience a high rate of mortality before reaching adulthood. (Islam and Belal Hossain, 2012)
There is limited information regarding parental investment in Indus Valley bullfrogs. One study analyzing the level of parental investment across 20 different frog families observed that less than 10% of all frog species exhibit signs of parental care. Furthermore, parental investment was absent in the family Dicroglossidae, which includes Indus Valley bullfrogs. It is likely that Indus Valley bullfrogs exhibit little to no parental investment beyond the act of mating and egg-laying. (McDiarmid, 1978)
Despite countless research studies, information on the age and longevity on Indus Valley bullfrogs is limited. An extensive research study conducted in 2005 concluded that they may live more than 7 years in the natural environment. There is also some evidence that Indus Valley bullfrogs live longer in tropical environments, but further research is required to confirm this. (Pancharatna and Kumbar, 2005)
Indus Valley bullfrogs are primarily nocturnal and solitary throughout most of the year, with the exception of mating season. Indus Valley bullfrogs commonly inhabit holes or dense vegetation near consistent sources of water, such as wetlands. They typically avoid forested areas and coastal regions. Although Indus Valley bullfrogs do spend time in water, they do not do so for very long. Instead, they spend time in surrounding vegetation, where they hide from predators and forage for prey. (Tripathi, 2018)
There is limited information on home ranges of Indus Valley bullfrogs, though they are likely limited to areas surrounding permanent bodies of water.
Indus Valley bullfrogs do not exhibit much intraspecific communication outside of their mating season. During mating season, males produce loud calls from their vocal sacs to attract females. Indus Valley bullfrogs also communicate using visual cues. They are visually oriented predators with acute vision. Males develop bright yellow coloration in the mating season, which likely plays a role in mate selection by females. There are no other specific forms of communication reported in literature regarding Indus Valley bullfrogs. However, they likely perceive chemical cues from predators, prey, and conspecifics in their environment. (Padhye, et al., 2008; Tripathi, 2018)
Indus Valley bullfrogs are opportunistic predators, considered to have rather unusual food habits. Their diet mostly consists of invertebrates, but they also eat small mammals and birds small enough to fit in their mouths. Stomach content analyses of Indus Valley bullfrogs have also reported plant matter and other materials, including human hairs and dung. There are also rare reports of Indus Valley bullfrogs eating juvenile snakes or other frogs. (Mishra, 2017; Mohanty and Measey, 2018)
The most common predators of Indus Valley bullfrogs are snakes (suborder Serpentes), mammals (class Mammalia), and other vertebrates. Asiatic water snakes (Xenochrophis melanozostus) in particular are the main predators of Indus Valley bullfrogs. Throughout the majority of the year, Indus Valley bullfrogs have olive-green or brownish-green coloration, which provides them camouflage in shallow water or near vegetation. Indus Valley bullfrogs spend much of their time in holes or near dense vegetation, in part to avoid detection by predators. (Gautam and Bhattarai, 2020)
Indus Valley bullfrogs have negative impacts on native ecosystems in Madagascar and the Maldives, where they were unintentionally introduced by humans. Indus Valley bullfrog tadpoles are large and prey on tadpoles of other frog species. Their presence in a water body is associated with high mortality rates of native tadpole populations.
In their native range, Indus Valley bullfrogs likely control the populations of pest species. They have a varied diet consisting of invertebrates, small mammals, and birds, some of which may carry disease or impact plant communities if left unchecked. Further research is needed to improve understanding of the impacts Indus Valley bullfrogs have on ecosystems. (Mohanty and Measey, 2018; Parajuli and Budha, 2006)
Indus Valley bullfrogs prey mostly on invertebrates, some of which can transmit diseases to humans. For example, Indus Valley bullfrogs feed on mosquito larvae and thus reduce the number of mosquitoes that survive to adulthood. This reduces the chances of adult mosquitoes spreading harmful diseases to diseases. Other invertebrates, as well as mammals and birds that Indus Valley bullfrogs eat, may also be crop pests. Therefore, it is likely that Indus Valley bullfrogs control populations of agricultural pests to some extent. (Mohanty and Measey, 2018)
There are no known negative economic impacts of Indus Valley bullfrogs on humans. However, Indus Valley bullfrogs are invasive in Madagascar and the Maldives. They are known to negatively impact populations of native frogs in these areas, which can produce cascading effects on the health of native ecosystems. Though the economic impacts of such ecosystem disturbances can be difficult to quantify, it is possible that Indus Valley bullfrogs have indirect negative effects on economics in their invasive range.
Indus Valley bullfrogs are considered to have stable populations throughout their geographic distribution. They have no special status on the IUCN Red List, CITES appendices, U.S. Federal List, or State of Michigan List. (Padhye, et al., 2008)
Megan Garrison (author), Colorado State University, Galen Burrell (editor), Special Projects.
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
uses sound to communicate
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
an animal that mainly eats the dung of other animals
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
An animal that eats mainly plants or parts of plants.
referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.
marshes are wetland areas often dominated by grasses and reeds.
A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.
Having one mate at a time.
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
islands that are not part of continental shelf areas, they are not, and have never been, connected to a continental land mass, most typically these are volcanic islands.
found in the oriental region of the world. In other words, India and southeast Asia.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
a wetland area that may be permanently or intermittently covered in water, often dominated by woody vegetation.
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
uses sight to communicate
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