YABBY - (YABBIE)
Yabbies, are a type of inland freshwater crayfish found in Australia.
They are a crustacean (ie External skeleton = hard shell)
Scientific name is "Cherax destructor"
Smooth shells and are a range of coloured depending upon the colour
of their habitat (mud silt water etc)
Their colour therefore ranges from greens to yellows, browns to blacks and red or Blue
Mostly though the colours are drab due to them being found mostly in mud and silt
Yabbies usually grow to a length of up to 150 mm depending upon conditions
They have eyes on the end of little stalks
They also have 3 sets of antennae which provide the yabby with the ability to touch things
Yabbies have gills like fish so they can "breathe" under water
Like most crayfish the Yabbies have 2 large "pincer like" claws at the front
These are used mainly for defence against other Yabbies and predators as well as for grasping food, and for digging burrows
Yabbies have 4 sets of "walking legs and a long thick "tail"
They live in dams, waterholes, billabongs, creeks, irrigation channels, etc (inland "still" waters) of mainland Australia.
Originally they were native to the Darling and Murray river catchment areas and other close smaller catchments "see map"
They house themselves in small tunnels that they dig into the sides of the waterhole, dam etc
They keep the waterways clean by eating rotten vegetation (leaves and plants) and small remains of dead animals and fish.
They also feed on fresh plants worms and insects and can be cannibalistic (eat other Yabbies)
In courtship the male Yabby uses his claws to impress the female
After mating the male has no interest at all in the upbringing of the young yabby
The eggs which have been fertilised lies between the Females rear legs so she curls her tail around them to cover them (see "Fern Valley" pic opposite).
Hundreds (100 to 1000) are laid at a time though not all hatch
After birth the young hang onto their mother for 4 to 6 weeks
At this stage they are known as "Larvae"
Birds eg Kookaburras...
Yabbies shells are rigid so as yabbies grow they become too big for their shells
They discard their old shell and within 1 to 2 days their newly revealed shell, (which was originally soft) becomes hard