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Growling grass frog

The Growling grass frog (Ranoidea raniformis), also known as the southern bell frog, is a large, robust species of tree frog in the family Pelodryadidae, characterized by its distinctive deep, growling advertisement call and bright to olive-green dorsal coloration marked with irregular brown or bronze blotches.^[1]^[2] Adults typically measure 60–104 mm in snout-to-vent length, with females larger than males, and feature warty skin, prominent tympana, and pale undersides often tinged with yellow or blue on the thighs.^[1]^[3] Tadpoles are large, up to 110 mm, with a greenish-yellow dorsal surface and a prolonged aquatic larval stage lasting 2–15 months.^[3] Native to southeastern Australia, including New South Wales, Victoria, South Australia, and Tasmania, the species inhabits a variety of permanent and semi-permanent freshwater bodies such as swamps, marshes, slow-flowing streams, farm dams, and irrigation channels, preferring sites with emergent and submerged vegetation like cumbungi and pondweeds for cover and breeding.^[1]^[2]^[3] It has been introduced to New Zealand, where small populations persist.^[4] Breeding occurs primarily in spring and summer, with males calling diurnally and nocturnally from water's edge or floating vegetation to attract females, who deposit eggs in cohesive masses on the water surface that hatch within 3–4 days.^[1]^[3] The frog is highly mobile, capable of dispersing up to 1 km in a day, and overwinters in nearby vegetation, logs, or burrows.^[3] Once widespread and common, the growling grass frog has undergone severe population declines since the 1980s, particularly in upland areas, leading to its classification as Vulnerable on the IUCN Red List (as of 2023) and under Australia's Environment Protection and Biodiversity Conservation Act 1999, with populations severely fragmented and continuing to decline.^[4]^[2]^[3] Major threats include habitat destruction and modification from agriculture, urbanization, and altered hydrology; the amphibian chytridiomycosis disease; predation by invasive species such as mosquitofish, foxes, and cats; and climate change impacts on water availability and temperature regimes.^[4]^[2]^[3] Conservation efforts focus on habitat restoration, disease management, and threat mitigation through protected areas and recovery plans in regions like greater Melbourne and southwestern Victoria, where some populations remain relatively stable.^[2]^[3] In 2025, a taxonomic revision reclassified the species from the genus Litoria to Ranoidea within the family Pelodryadidae.^[5]

Taxonomy

Classification

The growling grass frog is classified within the domain Eukarya, kingdom Animalia, phylum Chordata, subphylum Vertebrata, class Amphibia, order Anura, family Pelodryadidae, genus Ranoidea, and species R. raniformis.^[6]^[7] The species was originally described as Chirodryas raniformis by Keferstein in 1867, based on a specimen from Australia with a type locality listed as "Australien" (later specified as possibly New South Wales).^[6]^[5] Keferstein's description was initially synonymized with Hyla aurea in 1868 but was later recognized as distinct.^[8] Following a comprehensive phylogenomic analysis, the species was transferred from the genus Litoria to Ranoidea in a 2025 taxonomic revision of the Pelodryadidae family, reflecting its phylogenetic placement within a clade of predominantly ground-dwelling and semi-aquatic Australian frogs. As of November 2025, this revision is not yet universally adopted, with some sources continuing to use Litoria raniformis.^[5]^[9]^[10] Synonyms include Litoria raniformis (used until 2025), Hyla aurea raniformis, Hyla aurea major, and Ranoidea major.^[6] The placement in Pelodryadidae distinguishes it from true hylid frogs of the Northern Hemisphere, as this family represents a distinct Australo-Papuan radiation adapted to diverse Australian wetland and woodland environments.^[5]

Etymology

The common name "growling grass frog" originates from the species' deep, guttural mating call, which resembles a growl, and its frequent occurrence in grassy wetlands.^[11]^[12] However, the "grass frog" designation is misleading, as the species belongs to the tree frog family Pelodryadidae rather than the African grass frog genus Ptychadena. Alternative common names include "southern bell frog," alluding to a resonant, bell-like aspect of its vocalizations in certain contexts; "warty swamp frog," referencing its textured, warty dorsal skin and affinity for swampy environments; and erroneously "green frog," stemming from superficial color similarities and taxonomic confusion with other green-hued species like the green and golden bell frog (Ranoidea aurea).^[13]^[14]^[15] The binomial scientific name Ranoidea raniformis reflects both morphological and phylogenetic considerations. The genus Ranoidea, newly erected in 2025 from the former broad genus Litoria based on genomic evidence, derives from the superfamily Ranoidea and evokes a resemblance to the true frogs of the family Ranidae in habitus and form. The specific epithet raniformis combines the Latin rana (frog) with -formis (in the shape of), denoting "frog-shaped" and underscoring the species' archetypal anuran morphology as perceived in 19th-century taxonomy.^[5]^[16]^[15] Originally described as Chirodryas raniformis by German zoologist Johann Wilhelm Keferstein in 1867 from specimens collected in Australia, the name has undergone revisions: it was transferred to Litoria in the 20th century to align with Australo-Papuan tree frogs, and reclassified to Ranoidea in 2025 amid a major phylogenomic restructuring of the family Pelodryadidae that split Litoria into 35 genera.^[7]^[17]^[18]

Description

Adult morphology

The growling grass frog (Ranoidea raniformis), also known as the southern bell frog, is a large species with adults reaching a snout-to-vent length (SVL) of up to 100 mm, though females are typically larger (average 70–100 mm) than males (average 50–70 mm).^[19]^[20] The body is robust, with long hind legs adapted for jumping and swimming, fully webbed toes on the hind feet, and expanded adhesive discs on the toe tips that facilitate climbing on vegetation and surfaces.^[20]^[9] The eyes are prominent with horizontal pupils, and a distinct tympanum (eardrum) is visible behind each eye.^[9] Dorsally, the skin is warty and granular, featuring numerous small tubercles and shallow bumps that give a rough texture, often accented by a pale longitudinal stripe along the midline and dorso-lateral folds running from behind the eyes to the groin.^[20]^[9] Coloration varies but is typically mottled bright green to olive or bronze on the back, with irregular dark blotches; the venter is smooth and pale cream to white.^[19]^[20] Hidden surfaces, such as the thighs and groin, display striking blue-green flash colors, sometimes flecked with yellow, which are revealed during movement.^[20]^[15] Sexual dimorphism is evident in size, with females larger than males, and in breeding males, which develop black nuptial pads on the inner thumbs for amplexus and a mottled dark throat.^[21]^[15] Compared to the similar green and golden bell frog (Ranoidea aurea), the growling grass frog has a rougher, more warty dorsal skin with fewer prominent ridges and less extensive yellow markings along the sides.^[9]^[15]

Larval stage

The tadpoles of the growling grass frog (Ranoidea raniformis) reach a total length of 80–110 mm, with occasional individuals up to 130–150 mm, featuring an elongated body and a deep, powerful tail fin that facilitates agile swimming near the water surface.^[22]^[23] Newly hatched tadpoles are greyish-black or dark brown, while older larvae exhibit variable coloration ranging from dark velvety black-brown to green, light yellowish-grey, or pinkish-grey with yellowish tail fins; individuals approaching metamorphosis often develop a yellowish-pink sheen or golden markings along the sides.^[22] The belly is typically translucent, allowing visibility of internal structures.^[22] Key morphological features include a large oral disc adapted for filter-feeding algae and detritus, equipped with two upper and three lower rows of labial teeth—the inner rows divided—and bordered by a narrow band of papillae; external gills are present only briefly after hatching and are soon resorbed.^[22] Eggs hatch 2–4 days after deposition, with tadpoles completing metamorphosis in approximately 3 months under warm conditions (around 23°C), though the larval period can extend to 2–15 months in cooler regions where development is delayed.^[22]^[23] These tadpoles demonstrate notable adaptations for survival in temperate environments, including the ability to overwinter in a dormant state during cold periods, tolerating low temperatures that prolong the larval phase without mortality. They are also physiologically equipped for aquatic life, excreting nitrogen as ammonia (ammonotelic) to maintain balance in water, and their active swimming behavior helps them access oxygenated surface layers in potentially stagnant habitats.^[22]

Distribution and habitat

Geographic range

The growling grass frog (Litoria raniformis) is native to south-eastern Australia, with its distribution spanning from the south-eastern corner of South Australia—particularly along the Murray River—throughout most of Victoria and New South Wales, and extending to the eastern half of Tasmania.^[23] The species is absent from arid interior regions of the continent and occurs at elevations ranging from sea level to approximately 1,300 m.^[7] Historically, the frog was once widespread in wetlands across a broad area from Adelaide in South Australia to Sydney in New South Wales, representing one of the most common species in these habitats prior to the late 1970s.^[23] Since the 1980s, its range has contracted markedly, with notable disappearances from higher elevations, the Australian Capital Territory, and parts of the Mt Lofty Ranges and Adelaide Plains in South Australia.^[23] Current native populations are fragmented, particularly in urbanizing areas around Melbourne where habitat isolation has led to isolated remnants, while more stable groups persist in rural wetlands such as those in north-western and south-western Victoria, the Lower Murrumbidgee and Murray River systems in New South Wales, and eastern Tasmania.^[24]^[23] Outside its native range, L. raniformis was introduced to New Zealand in 1867 on the South Island from Melbourne stock and has since become established across wetlands in both the North and South Islands.^[14] Populations in New Zealand remain widespread and generally stable, though some localized declines have occurred, particularly in North Island wetlands influenced by chytrid fungus.^[25]^[14]

Preferred habitats

The growling grass frog (Litoria raniformis) primarily inhabits permanent or semi-permanent freshwater bodies, including swamps, ponds, lakes, farm dams, irrigation channels, quarries, and slow-flowing rivers or streams.^[26]^[27]^[28] These environments provide essential conditions for breeding and survival, often featuring large, continuous wetland areas that undergo regular flooding cycles.^[28] Vegetation plays a critical role in habitat selection, with the frog associating closely with emergent reeds such as common reed (Phragmites australis), cumbungi (Typha orientalis), and tall spike-rush (Eleocharis sphacelata), as well as submerged plants like curly pondweed (Potamogeton crispus) and hornwort (Ceratophyllum demersum).^[27]^[28] Floating vegetation, including duckweed (Lemna spp.) and ferny azolla (Azolla pinnata), offers additional cover for shelter and breeding sites, while grassy margins around water edges support basking and foraging activities.^[27] High aquatic vegetation cover—typically 20-80% depending on wetland permanence—is preferred to enhance occupancy probabilities.^[27] Microhabitat preferences emphasize sunny, shallow edges of water bodies for thermoregulation, where adults can bask during the day and engage in nocturnal calling and foraging among emergent or floating vegetation, bank-side rocks, or open pasture.^[27]^[28] The species shows tolerance for brackish conditions, with electrical conductivity up to approximately 10,000 μS/cm, allowing occupation of slightly saline wetlands in certain regions.^[27] Habitat use varies by life stage: adults occupy vegetated wetlands for shelter under logs, rocks, or dense vegetation, particularly during non-breeding periods, while dispersing to flooded areas in spring and summer for reproduction.^[28] Tadpoles develop in open still or slow-moving water, requiring permanent or seasonally flooded sites free of predatory fish for successful metamorphosis, which can take 2–15 months, depending on temperature and location.^[26]^[28] Juveniles seek moist refugia in wetlands post-metamorphosis, rapidly growing to maturity within about four months and utilizing similar vegetated margins as adults.^[27] Key habitat requirements include water depths of 0.5-2 meters to support vegetation growth and tadpole development, with deeper areas exceeding 1.5 meters ideal for sustained wetland quality.^[27]^[28] Connectivity to floodplains is essential, facilitating breeding cues and dispersal corridors between wetland populations, often within a 1 km radius for optimal occupancy.^[27]^[28]

Ecology and behavior

Diet and foraging

The growling grass frog (Litoria raniformis) is an opportunistic carnivore with a varied diet consisting primarily of invertebrates such as insects (including crickets, beetles, moths, and cicadas), spiders, and crustaceans, supplemented by small vertebrates like tadpoles, fish, and other frogs, including conspecifics.^[28]^[29] Less commonly, it preys on lizards and snakes.^[28] Tadpoles are also herbivorous-detritivorous, feeding on algae and detritus before incorporating small invertebrates or engaging in cannibalism as they grow.^[25] As a sit-and-wait ambush predator, the growling grass frog forages mainly at night, using visual cues to detect prey from perches on emergent vegetation, rocks, or bare ground near water edges.^[28]^[30] It employs lunge strikes to capture prey within reach, often swallowing items whole.^[31]^[32] Foraging activity peaks in late summer and autumn, aligning with higher prey availability in wetlands.^[33] In wetland ecosystems, the growling grass frog serves as a mid-level predator, helping regulate invertebrate populations and serving as prey for larger animals like birds and mammals.^[10]

Reproduction

The growling grass frog (Litoria raniformis) breeds during spring and early summer in its native range, typically from August or September to January or February, with occasional extension into March or April depending on environmental conditions.^[22] Breeding activity is triggered by rainfall events that fill or replenish wetlands, combined with water temperatures between 11°C and 16°C, which stimulate chorusing behavior among males.^[2]^[22] In southern Australia, peak breeding coincides with warmer months when daytime air temperatures often exceed 15°C, promoting female responsiveness to male calls.^[2] Mating is initiated by males calling from positions floating in open water or at the edges of wetlands, producing a characteristic growl or drone to attract females, often in large choruses that occur day or night.^[22]^[34] Once a female approaches, the male clasps her in axillary (pectoral) amplexus, a firm embrace around the upper body that stimulates egg release and deposition.^[22] The species exhibits a polygamous mating system, with males capable of amplexus with multiple females during a single breeding season, and females potentially laying more than one clutch if conditions allow repeated matings.^[22] Females deposit eggs in gelatinous, floating rafts or mats attached to submerged vegetation, with each clutch containing 1,900 to 4,000 pigmented eggs measuring 1.3–1.5 mm in diameter within 2–2.5 mm capsules.^[29]^[2]^[22] These rafts typically sink within 12 hours after deposition, allowing eggs to develop in shallow water.^[2] There is no parental care, with eggs and resulting tadpoles left to develop independently.^[2] Sexual maturity is reached after 2 years of age, corresponding to a snout-vent length of approximately 55 mm. In the wild, individuals have a lifespan of up to 4–5 years, though most populations show a majority of adults aged 2–3 years due to environmental pressures.^[35]

Vocalization

The primary vocalization of the growling grass frog (Litoria raniformis) is the advertisement call produced by males, consisting of a deep growl typically lasting about 1 second and described onomatopoeically as "crawark-crawark-crok-crok."^[34] This call features a long introductory note followed by two or three short grunts, with dominant frequencies around 1200 Hz and a frequency range of 300–3000 Hz, including secondary peaks at approximately 500 Hz and 1300 Hz.^[36]^[37] The call's low-frequency components facilitate long-distance transmission in wetland environments, allowing choruses to be audible over 1 km.^[36] Call variations include the growl, which may extend to about 3 seconds in some instances, and a faster variant comprising a train of rapid grunts lasting 0.26–1.07 seconds (mean 0.58 seconds), both serving as advertisement signals in choruses.^[36] Males also produce encounter calls, such as short grunts (duration 0.19 seconds, pulse rate 25.7 Hz, dominant 600–800 Hz), during interactions with other males, potentially for territorial defense.^[36] Release calls, manifested as high-pitched squeals (~1 second, emphasized at 3.5–6 kHz), are emitted by both sexes in distress, such as when grasped by predators or conspecifics.^[36] These variations enable species-specific communication, distinguishing L. raniformis calls from those of the closely related green and golden bell frog (Litoria aurea), which features a distinct drone absent in L. raniformis.^[36] Males typically produce these calls while floating in open water or on emergent vegetation, primarily at dusk or after dark during the breeding season from October to March, when choruses form in response to suitable conditions.^[34]^[37] Calling activity peaks in warmer months and increases with rising air temperatures, with choruses exhibiting both discrete bursts and prolonged sessions lasting up to several hours.^[38]^[36] These vocalizations play a key role in mate attraction during reproduction. Recordings of L. raniformis calls have been available since the 1970s, with early analyses contributing to taxonomic and bioacoustic studies, and they remain essential for contemporary population surveys through call playback and monitoring techniques.^[22]^[39]

Conservation

Status and population trends

The growling grass frog (Litoria raniformis) is classified as Vulnerable on the IUCN Red List, with the assessment conducted in 2023 under criteria A2ace, indicating an observed, estimated, projected, or suspected population reduction of at least 30% over three generations due to habitat loss, disease, and other factors.^[4] In Australia, the species holds national Vulnerable status under the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).^[10] Regionally, it is listed as Vulnerable under Victoria's Flora and Fauna Guarantee Act 1988, as per the February 2024 threatened list.^[40] In Tasmania, it is also Vulnerable under the Threatened Species Protection Act 1995, though populations there have shown relative stability compared to mainland declines, with an estimated 5,000–10,000 adults persisting.^[41]^[21] Population trends indicate a marked decline across the species' range since the 1980s and 1990s, with reductions exceeding 50% in some areas, including local extirpations from urban Melbourne and parts of the Australian Capital Territory (ACT).^[42]^[43] Remaining populations are highly fragmented, with global mature individual estimates fewer than 10,000, concentrated in isolated wetland sites. Some stabilization has been observed in managed wetlands through targeted conservation.^[4] Monitoring efforts, including annual call playback surveys and auditory detection, have tracked these trends since the 1990s, particularly in Victoria and New South Wales, providing data on occupancy and abundance changes.^[4]^[44]

Threats

The growling grass frog (Litoria raniformis) faces significant habitat loss primarily due to urbanization, agricultural expansion, and wetland drainage, which have drastically reduced available breeding sites across its range. In the southern Murray-Darling Basin, more than 80% of native vegetation has been cleared, severely impacting wetland habitats essential for the species. Urban development around Melbourne has further exacerbated habitat degradation and fragmentation, isolating populations and limiting dispersal.^[45]^[24]^[2] River regulation and altered water management practices, including dam construction and irrigation diversions, have disrupted natural flooding cycles critical for breeding, as the species relies on seasonal inundation of wetlands. Prolonged droughts, intensified by these modifications, further dry out temporary water bodies, preventing reproduction and leading to population crashes.^[10]^[46] Chytridiomycosis, caused by the chytrid fungus Batrachochytrium dendrobatidis, has been a major driver of die-offs since the 1990s, with the growling grass frog showing high susceptibility to this skin infection that disrupts electrolyte balance and leads to cardiac arrest. The disease emerged widely in Australia during this period, contributing to rapid declines in the species' abundance.^[10]^[47]^[48] Introduced predatory fish, particularly the eastern gambusia (Gambusia holbrooki), pose a direct threat by consuming eggs and tadpoles in breeding wetlands, with this invasive species proliferating in modified waterways. Pollution from agricultural pesticides, herbicides, and fertilizers contaminates water bodies, impairing frog development, reducing breeding success, and increasing vulnerability to diseases. Climate change compounds these issues by exacerbating wetland drying through reduced rainfall and higher evaporation rates, while elevated ultraviolet-B radiation from ozone depletion may harm basking individuals.^[10]^[2]^[49] In urban fringes such as those around Melbourne, these threats interact synergistically: habitat fragmentation increases exposure to predators and pollutants, while altered hydrology and disease amplify mortality rates, creating compounded risks for remnant populations.^[24]^[46]

Conservation efforts

Habitat restoration efforts for the growling grass frog (Litoria raniformis) focus on rehabilitating wetlands through revegetation and hydrological management to support breeding and dispersal. In Victoria, projects emphasize re-vegetating emergent reeds and aquatic plants in degraded wetlands to provide shelter and foraging sites, with positive responses observed in restored sites featuring floating or emergent vegetation.^[50]^[51] The Melbourne Strategic Assessment program collaborates with Melbourne Water to create new breeding wetlands and secure conservation areas, enhancing connectivity between fragmented populations in urbanizing landscapes.^[47] In the Murray-Darling Basin, environmental watering regimes simulate natural flooding to inundate floodplains, triggering breeding events and maintaining wetland habitats critical for the species.^[52]^[53] Policy protections underpin these initiatives, with the species listed as vulnerable under the federal Environment Protection and Biodiversity Conservation (EPBC) Act 1999, mandating environmental impact assessments for actions that may significantly affect its habitat.^[54] In Victoria, the Flora and Fauna Guarantee (FFG) Act 1988 supports action statements that designate reserves and guide land management to protect key sites, including farm dams and swamps in southwestern regions.^[50]^[55] Disease management targets chytridiomycosis, a major threat, through protocols in translocation programs that include quarantine, antifungal treatments like itraconazole baths, and site biosecurity to prevent pathogen spread.^[56]^[57] Ongoing research explores chytrid resistance in populations, with studies assessing infection dynamics in cooler climates to inform refugia creation.^[58]^[50] Monitoring and research efforts involve community-based surveys using the FrogID app to track distribution and abundance, building public awareness and data for adaptive management.^[59]^[60] Genetic studies, such as a 2015 analysis of Melbourne's urban-fringe populations, reveal low connectivity and diversity, guiding restoration to enhance gene flow via habitat corridors.^[61] Success stories include population stabilization in managed farm dams modified with aquatic vegetation and refuge zones, where enhanced hydroperiods have supported persistent breeding.^[62]^[63] Reintroduction trials, such as those at Winton Wetlands in Victoria, have established new populations in restored habitats absent since 1970, demonstrating viability through captive-bred releases and monitoring.^[64]^[65]

Captivity

As a pet

Keeping growling grass frogs (Litoria raniformis, also known as southern bell frogs) as pets is subject to strict legal regulations in Australia due to their protected status under state wildlife acts. In most Australian states and territories, such as New South Wales and Victoria, native frogs are protected wildlife, requiring a specific license or permit—such as a biodiversity conservation license or frog keeper license—to possess them legally.^[66]^[67] Wild capture is illegal across all states, as frogs are considered protected species under legislation like the National Parks and Wildlife Act in New South Wales.^[68] In New Zealand, where the species is an introduced and naturalised species considered a potential vector for diseases like chytridiomycosis to native frogs, it is listed in Schedule 5 of the Wildlife Act 1953, meaning it is not protected. Keeping as pets is permitted, but release into the wild is illegal to prevent ecological risks.^[69]^[70] Suitable housing for pet growling grass frogs must mimic their semi-aquatic habitat, with a large vivarium providing both land and water areas to accommodate their active, ground-dwelling nature. A minimum enclosure size of 60 cm length by 45 cm width by 45 cm height is recommended for one to two adults, allowing space for a shallow water pool (at least one-third of the floor area, 10-15 cm deep) for swimming and soaking, alongside a dry land section with substrate like sphagnum moss or leaf litter for burrowing.^[71] The setup should include UVB lighting (5.0 spectrum, 10-12 hours daily) to support vitamin D synthesis, as well as multiple hiding spots such as cork bark, PVC pipes, or live plants like Pothos for security and climbing.^[41] Water quality is critical, requiring dechlorinated, filtered water changed weekly to prevent bacterial growth, with a gentle filtration system to maintain slow-moving conditions.^[72] Basic care involves a diet of live insects to meet their carnivorous needs, fed every 2-3 days to avoid obesity. Appropriate prey includes gut-loaded crickets, dubia roaches, earthworms, and locusts dusted with calcium and multivitamin supplements, comprising 10-20% of the frog's body weight per feeding session.^[73] Environmental parameters must be maintained at 20-30°C (with a warm basking spot up to 27°C to reduce chytrid susceptibility) using under-tank heaters or ceramic heat emitters, and humidity levels of 70-90% achieved through daily misting and the water feature.^[73] Annual veterinary health checks are essential, focusing on screening for chytridiomycosis via skin swabs, as captive amphibians are prone to this fungal disease; early detection allows antifungal treatments like itraconazole baths.^[74] Specimens must be sourced exclusively from captive-bred stock obtained through licensed breeders or registered suppliers, as wild collection is prohibited in Australia and contributes to population declines.^[75] In New Zealand, sourcing is similarly restricted to prevent further spread of the invasive population.^[15] Challenges in captive care include the species' high susceptibility to stress from improper handling or enclosure disturbances, which can suppress immunity and lead to lethargy or refusal to eat.^[76] Additionally, they are vulnerable to infectious diseases like chytridiomycosis and bacterial dermatitis (red leg syndrome) if temperatures drop below 23°C or humidity fluctuates, necessitating vigilant monitoring and quarantine for new additions.^[77] Poor water quality or inadequate UVB exposure can also cause metabolic bone disease, underscoring the need for experienced keepers.^[78]

Breeding programs

Captive breeding programs for the growling grass frog (Litoria raniformis) are primarily managed by Australian zoos affiliated with the Zoo and Aquarium Association (ZAA), the Amphibian Research Centre, and conservation organizations such as Winton Wetlands and Nature Glenelg Trust, in collaboration with government agencies like the Victorian Department of Energy, Environment and Climate Action. These initiatives aim to produce disease-free individuals for reintroduction to bolster declining wild populations, with a focus on maintaining genetic diversity to support long-term viability.^[79]^[80]^[81] Breeding techniques include the use of simulated wetland enclosures to mimic natural habitats, such as outdoor ponds with aquatic vegetation and controlled water levels at facilities like Winton Wetlands' quarantine and laboratory setup. Hormone induction, involving gonadotropin-releasing hormone agonists and dopamine antagonists, has been successfully applied to stimulate spermiation, courting behavior, and spawning in captive adults. Genetic management strategies, including pairing individuals from diverse wild sources, help prevent inbreeding depression, as outlined in ZAA protocols that have achieved breeding up to the F4 generation. Head-starting programs raise tadpoles to juvenile stages in controlled environments to improve overwintering survival before release.^[80]^[82]^[79] Success has been demonstrated through consistent breeding in captivity over the past 15 years, with programs like Nature Glenelg Trust's Clayton Bay facility raising initial batches of 35 tadpoles to maturity and preparing for production of hundreds to thousands more for release. At Winton Wetlands, 30 wild-sourced adults were translocated in 2023, quarantined, and moved to breeding enclosures, where calling and mating behaviors were observed in subsequent seasons, establishing a foundational captive population. As of the 2024/2025 breeding season at Winton Wetlands, increased breeding behavior was observed among the captive population, though no egg laying occurred; the team remains optimistic for future spawning.^[83] These efforts have contributed to reintroductions, such as the planned release of captive-bred juveniles into Victorian wetlands to restore local populations.^[81]^[84]^[64] Challenges include the high risk of chytrid fungus (Batrachochytrium dendrobatidis) infection, necessitating strict biosecurity and quarantine measures during translocation and rearing. Post-release survival rates remain low, estimated at 4-14% during active seasons based on mark-recapture studies, due to predation, habitat quality, and disease exposure in the wild. Limited funding and expertise for long-term husbandry further constrain program scale.^[79]^[85] These breeding programs integrate with broader wild conservation by releasing head-started froglets into restored wetlands, such as those enhanced under the Melbourne Strategic Assessment, to support metapopulation connectivity and research on threat mitigation. Monitoring via audio detection and genetic sampling informs adaptive management, linking captive outputs to habitat protection efforts.^[80]^[47]

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The growling grass frog is a large frog (females may exceed 100 mm in length) that varies from dull olive to bright emerald-green on the back. (dorsum), with ...Missing: morphology coloration sexual dimorphism<|control11|><|separator|>
[20]
[PDF] Growling Grass Frog Litoria raniformis
Males generally call when floating in open water among vegetation. The call is a growl which lasts for about 1 second-. “crawark-crawark-crok-crok”. Male Growl-.
[21]
[PDF] Green and Golden Frog, Litoria raniformis
The Green and Golden Frog Litoria raniformis is a large aquatic frog commonly reaching a maximum length of up to 80mm and weighing up to 40g.
[22]
A review of the biology of the Southern Bell Frog Litoria raniformis ...
Introduction. The Southern Bell Frog Litoria raniformis is, like a number of other Australian frog species, considered to be threatened with extinction.Missing: etymology | Show results with:etymology
[23]
[PDF] National Recovery Plan for the Southern Bell Frog Litoria raniformis
Tadpoles have an aquatic period lasting 2 – 15 months, grow to 110 mm in total length and, in the later stages of development, have a characteristic green to ...Missing: adaptations | Show results with:adaptations
[24]
Genetic structure and diversity of the endangered growling grass ...
Aug 26, 2015 · The growling grass frog (Litoria raniformis) is listed as vulnerable to extinction in Australia, and endangered in the state of Victoria.
[25]
Southern Bell Frog - NZFrogs
The southern bell frog, also known as the growling grass frog in Australia, Ranoidea raniformis ... IUCN. Adults are generalist feeders and consume a wide ...
[26]
[PDF] Guidelines for managing the endangered Growling Grass Frog in ...
Post-metamorphic growth rates are also rapid, and both sexes can reach sexual maturity within 4 months of metamorphosis (G. Heard unpubl. data). On average ...Missing: dimorphism | Show results with:dimorphism
[27]
[PDF] Significant impact guidelines for the vulnerable growling grass frog ...
The growling grass frog is also known as the southern bell frog, the green and golden frog, the warty frog, the warty bell frog and the green or warty swamp ...
[28]
Growling Grass Frog | Biodiversity of the Western Volcanic Plains
Breeding season: Spring and early summer. Females lay 1,900-3,900 pigmented eggs in a floating jelly raft which sinks soon after. Males generally call while ...<|control11|><|separator|>
[29]
Microhabitat preferences of the endangered Growling ... - ABSTRA CT
Litoria raniformis is known to forage nocturnally, pursuing prey including a variety of terrestrial and aquatic invertebrates, and small vertebrates (Pyke 2002 ...
[30]
[PDF] Southern Bell Frog - Department for Environment and Water
Tadpoles hatch two days later and hide in vegetation near the waters edge where it is shallower and warmer, then metamorphose into frogs in summer or autumn.
[31]
A review of the biology of the Southern Bell Frog Litoria raniformis ...
Mar 17, 2014 · Research conducted to date, however, reveals few, if any, differences in biology between the two species. They are similar in size, appearance, ...Missing: morphology | Show results with:morphology
[32]
Microhabitat preferences of the endangered Growling Grass Frog ...
Aug 7, 2025 · We examined nocturnal microhabitat preferences of the endangered Growling Grass Frog Litoria raniformis in lotic and lentic environments in ...
[33]
Growling Grass Frog - DCCEEW
Jul 10, 2023 · Scientific name. Litoria raniformis. EPBC status. Vulnerable. Found in. New South Wales, Victoria, South Australia, Tasmania. Description.Missing: distribution | Show results with:distribution
[34]
Frogs of Australia > Litoria raniformis / Growling Grass Frog - frogs.org
Adults are usually found close to or in water or very wet areas in woodlands, shrublands, and open and disturbed areas. Eggs and tadpoles can be found in ...
[35]
Longevity and larval development among southern bell frogs (Litoria ...
Dec 19, 2021 · For the metamorphosis assay, southern bell frog tadpoles were held back in their development by low temperatures and low food allocation for ...Missing: morphology | Show results with:morphology
[36]
Vocalisations of the green frogs <italic>Litoria aurea</italic> and ...
Three call types may represent male advertisement calls; ... 1983: The body and call forms of the frogs. Litoria aurea and Litoria raniformis in New. Zealand.
[37]
[PDF] Impacts of urban noise on acoustic communication in the growling ...
The peak breeding season of L. raniformis occurs in the warmer months of the year from October to March. Adult males have an average body size of 70 mm snout- ...
[38]
Interspecific variation in the phenology of advertisement calling in a ...
Aug 25, 2015 · dumerilii and Lit. raniformis increased as the temperature anomaly increased, the former responded more strongly to air temperature, while the ...
[39]
[PDF] Results of a Growling Grass Frog (Litoria raniformis) survey at Mount ...
Mar 6, 2017 · Litoria raniformis is known to occupy a variety of natural and artificial wetland habitats throughout its range, including permanent and ...
[40]
[PDF] Flora and Fauna Guarantee Act 1988 Threatened List - Environment
Giant Burrowing Frog. Heleioporus australiacus. Victoria. Critically Endangered. Growling Grass Frog. Litoria raniformis. Victoria. Vulnerable. Keferstein's ...
[41]
Green and Gold Frog - Threatened Species Link
The Green and Gold Frog (Litoria raniformis) is a large frog (up to 80 mm long) which occurs in Tasmania and south-eastern mainland Australia.
[42]
[PDF] Nature Conservation (Southern Bell Frog) Conservation Advice 2019
May 1, 2019 · The Southern Bell Frog is listed in the IUCN Red List under IUCN Criterion A2(a)(e) as endangered because of a drastic population decline ...
[43]
National Recovery Plan for the Southern Bell Frog Litoria raniformis
Nov 16, 2021 · Once one of the most common frogs in many parts of south-eastern Australia, the range of this species has declined markedly, and loss of ...
[44]
[PDF] Significant impact guidelines for the vulnerable growling grass frog
The growling grass frog is also listed as threatened under the Victorian Flora and Fauna Guarantee Act 1988, vulnerable under the South Australian National ...Missing: FFG | Show results with:FFG
[45]
[PDF] of the Southern Murray-Darling Basin - Wetland Revival Trust
More than 80% of native vegetation has been cleared and ... the Growling Grass Frog which include drought, habitat loss and altered flooding regimes.
[46]
Growling grass frog - Melbourne Strategic Assessment (MSA)
Jun 25, 2025 · Growling grass frogs are usually found in creeks, rivers, natural wetlands, quarry pits and dams.Missing: distribution | Show results with:distribution
[47]
Growling grass frog program - Melbourne Strategic Assessment (MSA)
Oct 31, 2024 · It has a low growling call, which sounds a bit like a motorbike. Up until the 1990s, growling grass frogs were once widespread throughout south ...<|separator|>
[48]
https://healthywaterways.com.au/case-studies/2021/building-high-quality-habitats-for-growling-grass-frogs
[49]
[PDF] Growling Grass Frog Habitat Design Standards
The purpose of the standards is to provide guidance on protecting and creating the various types of habitat required to support metapopulations. (multiple ...Missing: dimorphism | Show results with:dimorphism
[50]
[PDF] Growling Grass Frog (Litoria raniformis) - Action statement
Control introduced plants* • Optimise habitat availability by substituting introduced plants with native submergent, floating and emergent vegetation in and ...Missing: diet behavior
[51]
[PDF] Growling Grass Frog - North Central Catchment Management Authority
The Growling Grass Frog is one of the largest frog species in Australia. The females (60 ... predators such as trout and Gambusia and the Chytrid fungus.
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Environmental benefits - Water and catchments
Sep 8, 2023 · Many of the Murray floodplain wetlands provide habitat for several frog species, including the nationally threatened growling grass frog.
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Frogs in love hop into Murray-Darling Basin research - CSIRO
Aug 23, 2023 · Growling grass frog. "Some of the frogs make high frequency chirps ... frogs respond to environmental watering. They also want to add ...
[54]
Significant impact guidelines for the vulnerable growling grass frog ...
Nov 30, 2023 · The growling grass frog (Litoria raniformis) is listed vulnerable under the Environment Protection and Biodiversity Conservation Act 1999 ( EPBC ...
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Action statements - Environment
Oct 2, 2025 · Action statements are an important legislative tool used to inform conservation and investment decisions for the recovery of threatened species and communities.
[56]
Conservation translocations for amphibian species threatened by ...
Aug 28, 2021 · Here, we summarize two decades of published literature on translocations of Australian frogs threatened by chytridiomycosis—a fungal disease ...
[57]
Translocation of the threatened Growling Grass Frog Litoria raniformis
Nov 24, 2014 · Translocation is occasionally suggested as a last resort strategy for dealing with 'unavoidable' loss of Growling Grass Frog Litoria ...
[58]
Chytrid infection dynamics in frog populations from climatically ...
This study sought to assess the prevalence and intensity of chytridiomycosis among populations of a widespread frog species, Litoria raniformis, in cool ...
[59]
Citizen scientists growing our knowledge of 'Growlers' | CES
Nov 28, 2023 · The Growling Grass Frog (Litoria raniformis) is listed as a threatened species under both the Federal Environment Protection and ...
[60]
How you can help the elusive Growling Grass Frog in Wilsons Prom
Dec 11, 2023 · This "slimy-boi" (a Growling Grass Frog) is an ambush predator, sitting and waiting for prey to come past. Growling Grass frogs have been known ...
[61]
Genetic structure and diversity of the endangered growling grass ...
Aug 1, 2015 · The growling grass frog (Litoria raniformis) is listed as vulnerable to extinction in Australia, and endangered in the state of Victoria.
[62]
[PDF] Dams to habitat - Farm dam restoration for the Growling Grass Frog ...
We propose making simple modifications (planting aquatic vegetation and creating refuge habitat) to farm dams that are close to known populations to encourage ...
[63]
[PDF] Growling Grass Frog Conservation Management Plan, Wyndham ...
Mar 15, 2013 · Manage existing and created Growling Grass Frog wetlands, waterways, and terrestrial habitat to maintain suitable habitat for Growling Grass ...
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Reintroducing the threatened Growling Grass Frog to Winton ...
Apr 11, 2025 · It is considered to contain suitable natural and recovering habitats for the future breeding and survival of the Growling Grass Frog (Litoria ...Missing: stabilization | Show results with:stabilization
[65]
The reintroduction of Growling Grass Frogs to Winton Wetlands
By reintroducing GGF to the Winton Wetlands we hope to increase the number of wild populations of the GGF in Victoria and the species area of occurrence ...
[66]
Frog keeper licences - Environment and Heritage - NSW Government
Native frogs and amphibians are protected by law, so if you want to keep one as a pet you'll need a biodiversity conservation licence granted under the ...
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Caring for your pet amphibian - Agriculture Victoria
May 1, 2025 · In Australia, frogs are a protected species. You cannot legally capture them and keep them as pets. A frog kept as a pet must be registered with ...
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The ARC > Licensing and legal - frogs.org
All frogs (and tadpoles) are protected in NSW under the National Parks and Wildlife Act, and it is against the law to take them from the wild to keep as pets.
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Protection status changes to Wildlife Act | Beehive.govt.nz
Jun 11, 2010 · Southern bell frog (Litoria raniformis). Absolutely protected. Species poses a disease risk to native frogs through releases of pets into the ...
[70]
Code of Practice for the Welfare of Amphibians in Captivity
Jul 31, 2025 · A person in charge of amphibians has a legal obligation under the Prevention of Cruelty to Animals Act 1986 to ensure that each individual ...
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[PDF] frogs-captive-breeding.pdf - DCCEEW
There is a huge variety of substrates and cage furniture used in captive amphibian enclosures and each require different approaches to disinfection.
[72]
Introduced Frogs Husbandry guide - Aquarium World
A study in captivity also found that fewer frogs became infected and died when exposed to the chytrid fungus if they were housed at 27°C rather than 17°C or 23 ...
[73]
[PDF] tap-chytrid-fungus-2016.pdf - DCCEEW
With antifungal and supportive treatment, infected adult frogs and tadpoles in captive populations can fully recover from the disease. Of note, the situation in ...<|control11|><|separator|>
[74]
Can I keep a frog as a companion animal? - RSPCA Knowledgebase
May 9, 2024 · Laws on keeping frogs – Frogs and tadpoles are protected in all Australian states and territories and a license is required to keep them in ...
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Disorders and Diseases of Amphibians - All Other Pets
Amphibians are sensitive to their environments and easily become ill due to poor environmental conditions, such as poor water quality, poor diet, improper tank ...
[76]
[PDF] Correlates and consequences of chytridiomycosis for populations of ...
The Growling Grass Frog Litoria raniformis is officially listed as threatened at a national level and in every state in which it occurs. Declines in this ...
[77]
Common Diseases and Health Issues in Pet Tree Frogs
Dec 31, 2023 · Common issues include Chytrid Fungus, Red Leg, nutritional deficiencies, parasitic infections, skin disorders, respiratory infections, and ...
[78]
[PDF] Appendix 1 - ARAZPA Amphibian Action Plan - PDF version
These include: the Green and. Golden Bell Frog Litoria aurea, Growling Grass Frog L. ... Successful breeding programs for these species exist, either in Zoos or.
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GGF Information Sheet Stage 2 - Winton Wetlands
This is Stage 2 of our Growler Rewilding Project – translocating, quarantining, breeding and researching the establishment of a captive population as a major ...
[80]
The frogtastic Southern Bell Frog facility - Nature Glenelg Trust
Mar 19, 2020 · ... Growling Grass Frog – Litoria raniformis) conservation facility at Clayton Bay! We now have 35 frogs being carefully maintained by a band of ...
[81]
Hormonal Induction of Spermiation, Courting Behavior and ...
Aug 10, 2025 · The two exogenous hormones most commonly used to induce spermiation in anurans are luteinizing hormone-releasing hormone (LHRHa) and human ...
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Growling grass frogs breeding push moves species closer to Winton ...
Oct 12, 2023 · Efforts to reintroduce growling grass frogs to a north east Victorian wetland have reached a new stage · 30 frogs were brought to the Wetlands ...
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The life history and decline of the threatened Australian frog, Litoria ...
Aug 6, 2025 · Litoria raniformis is a large hylid ( Fig. 1) that suffered extensive population declines and disappearances late last century, likely caused by ...