Question
QUESTION: I have noticed since I moved to my property where I live 2 years ago, that in the spring there are holes in my yard about 4 inches diameter and have mud and rocks at the openings.  The mud and rocks apparently is coming from the ground because of water, but I'm not sure if it's animals.  The ground is still frozen 8 inches down and this particular set of holes was covered with a large black tarp.  Last spring the holes showed up in the front yard, and this year they are 75 feet away in the backyard.  The mud is sort of lumpy and dried now and looks like manure at first glance.  The rocks in the mud are large enough that I doubt it's animals.  What concerns me is that the holes in the front yard were quite close to the well head (25' away) and the holes in the backyard are practically over the septic.  The soil does not seem very robust and is quite clayish.  Does this just sound like poor drainage in the soil?
ANSWER: Hi April, it sounds like crayfish (or where I live they are called crawdads).  Not at all unusual to have them living in the water table not far below the surface. Other than being a nuisance with their collars of mud and rock around the holes, they're nothing to worry about.  Jim

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QUESTION: Thank you for the info.  I looked them up and they are found in the states.  I live in Saint John NB.  Would it still be crayfish?  I also have 3 yr old who plays out side.  

Answer
Hi Again. I believe that's what you have.  There are 150 or so North American species, most like warmer areas but several are cold water species.  I have a friend that has them in his yard and he's 1/2 mile from any surface water.
They seldom come to the surface in daylight. Your child is not likely to catch one.  Jim