A few years back we were asked to kick off a new series for Wild Magazine focusing on Australia’s endangered species. Ever since we’d seen this gorgeous picture taken by the very talented nature photographer Michael Williams we’ve been intrigued by the growling grass frog.
In the Australian amphibian world, the growling grass frog is what you might call a heavy hitter. One of our largest frog species, it measures 10 centimetres from head to tail, can live for up to 18 years and has a reputation as a ‘frog eater’. This reputation stems from an ability to hear the calls of other frog species. Growlers use this skill to home in on other frogs when on the hunt for food, adding them to a diet that includes insects, tadpoles, small lizards, fish and the occasional tiny bird.
Growlers live in large swamps, ponds and lakes (as well as artificial bodies of water) and are active during the warmer months. Growlers have a white, granular belly, and the skin on their back ranges from brown or dull olive to bright emerald green with black or bronze spots and lines. Their backs also carry large warts, a trait distinguishing them from the similar-looking green and golden bell frog.
Although they are most active at night, growlers also love basking in the warmth of mild, sunny days. They have no problems seeing during daylight hours and, if they hear you coming, will jump into the water with a distinctive ‘plop’—often the only way to know they are around during the day.
Their call is not dissimilar to the sound of an outboard motor struggling into action: ‘crawark-crawark-crok-crok’.
As recently as the early 1980s, growlers were considered common across much of south-east-ern Australia and Tasmania. Since then, their numbers have plummeted. Growlers can no longer be found in the ACT and are listed as threatened in NSW, Victoria, South Australia and Tasmania.
Suffering from habitat loss, predation by intro¬duced fish and overgrazing by livestock around the edges of wetlands, growler populations have also been hit hard by a frog-killing disease called chytrid fungus. This devastating disease, which creates a layer of matting under a frog’s skin that stops the skin from breathing, has already led to the loss of 70 frog species from Central and South America and could be behind the recent extinctions of eight Australian frog species.
The fungus is believed to have arrived in Australia in the 1930s with the introduction of the African clawed frog, which at that time was used in pregnancy tests. A woman’s urine sample was injected into the frog and, if the woman was pregnant, her urine would cause the frog’s ovaries to start producing eggs. What nobody realised at the time was that the African clawed frog was a carrier of the deadly chytrid fungus.
Although there is as yet no cure for this terrible disease, we can all take measures to prevent its spread in the wild, including the following:
- The spores of the fungus are waterborne so take care not to transport water or mud whenever you are near wetlands, dams, ponds or other bodies of water.
- Avoid touching frogs.
- Help educate others about the disease.