Yabbies. (apparently that's what they call them in Australia, so says the Wikepedia)
écrevisse. (in French)
What do you call them? We called them crawdads when I was little... but I think I lean toward the crawfish or crayfish camp these days.
Regardless of the name, I ran into quite a few of these crustaceans while on the lake in Michigan. The last time I recall seeing one was when I was quite young, after a heavy storm had blown through our urban neighborhood and flooded our street. There are no bodies of water near my childhood home, so I don't know if he floated in through the storm drains or what.
This guy, unfortunately, had very little life left in him, making for a good photo subject. I found one the next day that was a little more spirited, and he startled me by giving a good thrashing when I picked him up.