Corroboree Frog page 2

Life cycle and reproduction
The Corroboree Frog has a very different life cycle from other frogs. They don't start breeding until they are 4 years old. Adults hibernate over winter amongst snowgums, hiding under fallen leaves, bark, grass, rocks and logs.

In December (early Australian summer) the males travel to pools surrounded by sphagnum moss for summer breeding, unlike most other frogs which breed in spring. They dig a small burrow in the sphagnum moss for mating and nesting. Sphagnum is a kind of moss that holds a great deal of water, like a sponge. The moss is an important part of water catchment in the alpine regions, and essential for the Corroboree Frog.When the burrow is finished a male starts calling to attract females and to tell other males of his presence. He will attract up to about 10 females, 1 at a time. Inside the burrow the female lays up to 38 eggs (unlike other frogs, this is a small number. The Eastern Banjo Frog for example, lays up to 4000 eggs). As the eggs are laid, the male sheds sperm directly onto the eggs. Males stay in their nests most of the summer, trying to attract numerous females and build other nests if their first fills with eggs.

Each egg looks a bit like a marble, made of a jelly-like substance. They enlarge quickly, absorbing large quantities of water so they don't dry out during summer.

The tadpoles develop in about 4 weeks but, unlike other tadpoles, they stay in their egg jelly for about 6-7 months. They finally hatch out of the jelly when the nests are flooded by melting snow and autumn rains.They are 6 mm long and grow very slowly. All winter they remain as tadpoles, even under the ice. A year after the eggs were laid, as summer warms the water, the tadpoles change. First they grow back legs then front legs, then their tails disappear. They are now froglets about 8mm long, and they leave the nesting pools to travel to find places among the snowgums to hibernate through the winter.

Conservation status
The Corroboree Frog is Australia's most endangered frog. The cause of the decline is not clear, but may include a number of factors such as:
human activity: e.g 4 wheel drive vehicles destroying nesting grounds, the development of ski resorts
climate change and global warming: Corroboree Frogs have adapted to the cold, and winters may now not be long and cold enough for them to breed effectively
depletion of the ozone layer may play a role by increasing the ultra violet rays shining on shallow pools
disease: many frogs in Australia and overseas are affected by infections caused by a fungus
erosion and pollution of waterways used for breeding

The risks for the Corroboree Frog are increased by the small area they inhabitat and their specialised breeding pattern. Females only breed once a year, and the tadpoles are slow growing, spending many months in the shallow pools, which makes them vulnerable.

Actions to try and save the Corroboree frog
The NSW National Parks and Wildlife Service and others are observing and testing to try and find the reasons for the frog's decline. The Amphibian Research Centre is attempting to rear frogs from eggs in laboratories, aiming for the eventual release of adults back into the habitat.

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Click here to find out about the Amphibian Research Centre's Project Corroboree, see how you can help
http://frogs.org.au/corroboree/index.html

Click here for more information about the Southern Corroboree frog
http://www.abc.net.au/science/scribblygum/june2004/

Click here to find out about other endangered Australian frog species
http://frogsaustralia.net.au/conservation/frog-declines.cfm

Click here to find out how can we help threatened frog species

Back to Australian Animals
updated August 2006