Credit: Tnarg 12345 at the English-language Wikipedia, CC BY-SA 3.0 <http://creativecommons.org/licenses/by-sa/3.0/>, via Wikimedia Commons
Listen for the Growl!
The growling grass frog can be identified from the namesake growl produced by the males during the breeding season as they sit in a waterbody.
Their call acts to a attract a female who will then go on to deposit as many as 1,500 eggs. These hatch in to tadpoles which begin their life by developing in a waterbody before metamorphosing in to an adult.
They feed on a range of invertebrates along with small fish, lizards and such animals.
This species is classed as endangered due to a range of threats which have reduced their population including pollution, vehicle strikes, habitat destruction, introduced species and disease.
Read on to learn more about these amazing amphibians.
What does the Growling Grass Frog look like?
Growling grass frogs are variable in their color and pattern but most have an emerald green body with an irregular pattern formed of gold, bronze, brown and black coloration on their body. On the groins and thigh are turquoise blue spots.
Down the length of the body is a cream or brown stripe. This starts behind the eye runs back through the ear and onwards down the side of the body.
Across the body of the growling grass frog are a series of warts.
The growling grass frog is one of the largest frogs in Australia with females being significantly larger than males. During breeding season the males can also be distinguished by a yellow or black coloration under their throat.
They can measure up to 9cm (3.5in) long.
This species is regularly confused with the closely related green and gold bell frog (Litoria aurea). The two can be distinguished as the growling grass frog has a warty back compared to the smooth back of the green and gold bell frog.
How does the Growling Grass Frog survive in its habitat?
The feet of an adult growling grass frog are completely webbed to assist them with swimming in the water.
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What does the Growling Grass Frog eat?
Growling grass frogs are carnivores. The vast majority of their diet is made up of invertebrates but they have also been seen to consume small lizards and fish.
From observations they are believed to be a sit and wait predator.
Learn more about the Growling Grass Frog in this video from Wicked Wildlife on YouTube
Where do you find the Growling Grass Frog?
Australia is the native home of the growling grass frog. Here they can be found in New South Wales, Victoria, South Australia and Tasmania.
An introduced populations of the species has established in New Zealand, likely from wild releases. A population found in the Adelaide Hills of South Australia is also believed to have come from releases and is now likely to have died out.
Where can the Growling Grass Frog survive?
This species occurs in close proximity to water. Natural watercourses they make use of include lagoons, swamps and ponds. They also take advantage of man-made watercourses such as dams and unused quarries.
Their watercourses are located in woodlands and areas of improved pasture.
They will seek shelter under a log or rock.
Credit: Matt from Melbourne, Australia, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons
How does the Growling Grass Frog produce its young?
Males can be heard making their calls from August to April. Breeding occurs following localized flooding in their range. They will breed in a permanent swamp or other similar waterbody.
A female may lay up to 1,700 eggs which are deposited as a loose clump in the water. Initially these float at the surface before the clump breaks up and sinks.
They hatch 2-4 days after they were laid in ideal conditions but if it is colder it may take up to 5 days.
Larvae or tadpoles will swim freely in the water. During summer and autumn the larvae will develop before undergoing their metamorphosis during late summer or autumn. Some may overwinter and wait for the next season to undergo their metamorphosis.
Tadpoles are a large pinkish-grey color with small, yellow fins. They will take shelter in vegetation as they grow.
Females appear to first breed between 2 and 3 years old but they are capable of breeding in their first season after metamorphosis.
What does the Growling Grass Frog do during its day?
These animals are active by night when they will seek out food.
During winter their is a recognisable decrease in their activity levels.
As their name suggests the call is a growl which each last for roughly a second. This is primarily produced after rainfall.
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Predators and Threats
What stops the Growling Grass Frog from surviving and thriving?
Growling grass frogs are in decline across their range owing primarily to the introduction of non-native fish species from the genus, Gambusia. These have contributed to declines in their native range and also of the introduced population in New Zealand.
It is thought that introduced pathogens such as chtryid may also be contributing to their decline.
In Tasmania a major impact on the population has been the destruction of wetland habitats.
Small numbers are affected by road kills, pollution of waterways and increases in ultraviolet radiation due to the thinning of the ozone layer.
In some areas of Australia this species may be kept as a pet but it is likely these individuals are mostly captive bred rather than being taken from the wild.
This species may also be known as the southern bell frog, warty swamp frog or green and gold frog. This second name may cause confusion with the closely related green and gold bell frog (Litoria aurea).
Credit: Public Domain
Council, C., 2022. Growling Grass Frog - Cardinia Shire Council. [online] Cardinia.vic.gov.au. Available at: <https://www.cardinia.vic.gov.au/info/20003/pets_and_animals/314/growling_grass_frog> [Accessed 10 April 2022].
2022. Frogs of Australia. [online] Available at: <https://frogs.org.au/frogs/species/Litoria/raniformis/> [Accessed 10 April 2022].
2022. Growling Grass Frog. [online] Available at: <https://grasslands.ecolinc.vic.edu.au/fieldguide/fauna/growling-grass-frog#details> [Accessed 10 April 2022].
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Environment.gov.au. 2022. Litoria raniformis — Growling Grass Frog, Southern Bell Frog, Green and Golden Frog, Warty Swamp Frog, Golden Bell Frog. [online] Available at: <http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=1828> [Accessed 10 April 2022].
Hero, J., Gillespie, G., Lemckert, F., Littlejohn, M., Robertson, P., Brereton, R. & Brown, P. 2004. Litoria raniformis (errata version published in 2016). The IUCN Red List of Threatened Species 2004: e.T12152A86177064. https://dx.doi.org/10.2305/IUCN.UK.2004.RLTS.T12152A3327485.en. Accessed on 10 April 2022.
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