northernpintail

Burrowing Crayfish

The Question: What kind of animal builds a 3-4 inches (8-10 cm) high mound of mud balls with a 1 inch (2.5 cm) hole in the top? They look like mini volcanoes. I have found a couple of these in a swampy area near a river. I live in Michigan.

Submitted by: Debbie, MI

The Short Answer: Debbie, that sounds like one of the many species of burrowing crayfish (also called crawfish or crawdads). They dig tunnels down to dampness or even to the water table. And they push up muddy soil out of their burrow into a mini volcano shape, with a neat hole at the top. They’re generally nocturnal, so during the day, all you’ll see are the volcanoes, which can be quite numerous. I have spent most of my life in New England, where I don’t believe any of our native crayfish are burrowers. But when I lived in Wisconsin and Kentucky, they were very common. This site has a checklist of the native species of crayfish in Michigan: http://iz.carnegiemnh.org/crayfish/country_pages/state_pages/michigan.htm. There are two burrowers on the Michigan list, the digger crayfish (Fallicambarus fodiens), and the devil crayfish (Cambarus diogenes). The digger crayfish is primarily aquatic, but sometimes digs burrows out of the water. The devil crayfish, however, is a primary burrower, meaning that it lives most of its life in its burrow. So I’m going to guess that’s what you have. For a picture, go to: http://iz.carnegiemnh.org/crayfish/NewAstacidea/species.asp?g=Cambarus&s=diogenes&ssp

More Info: Burrowing seems to be a good strategy for crayfish, as crayfish all over the world have developed a very similar lifestyle of digging complex burrows down to damp or wet soil. Like all crayfish, burrowing crayfish have gills in their abdomen under their shell. The gills are capable of gaining oxygen from air instead of water as long as they are wet.

Crayfish, as you might expect, are classified with the clawed lobsters (Nephropidae. There are over 600 species of crayfish, in three main groupings. The Astacidae and Cambaridae are restricted to the northern hemisphere and centered on Asia and North America, respectively. The Parastacidae are distributed throughout South America and Australia. There are no crayfish native to Africa. The Cambaridae are centered on the Southeastern United States, which has the most diverse crayfish assemblage in the world – more than 300 species, a remarkable number when you realize that they seem to occupy very similar ecological niches. There is also an only slightly less impressive collection of crayfish species in Australia. But that part of the world includes some interesting oddballs, including burrowing crayfish that can live far from any surface water. Then there’s the Tasmanian Giant Crayfish, which can reach 4.5 kilograms (10 pounds) – big even by the standards of an ocean-dwelling lobster. To see a picture, go to: http://yhsbiology.wikispaces.com/Crustacea

Trivia #1: The Tasmanian Giant Crayfish (Astacopsis gouldi) is the largest freshwater invertebrate in the world.

Trivia #2: There are two continents with no native crayfish. One is Antarctica. The other is Africa.

The interesting science: It’s easy to understand why Antarctica might not have crayfish. It’s too cold there, and there is no ice-free fresh water. It hasn’t always been that way, and at least one crayfish has been found in Antarctica, so they probably lived there when the continent was located away from the pole. But why are there no native crayfish in Africa? To read more, click here to go to Curious Nature.net, where you’ll find a companion article about the strange distribution of crayfish species around the world.

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4 Responses

  1. Tom Says:

    Well, I should have checked this before I posted on burrowing crayfish, but I just learned that there are in fact burrowing crayfish in the New England states. They are all introduced species from other parts of the U.S., however. Introduced crayfish are a big problem all over the country, with the Rusty Crayfish being the worst culprit. In many areas, this crayfish has displaced all the native species. We should never release crayfish except in the lake or stream from which they came. Releasing bait crayfish is a major contributor to the problem.

  2. Paul Cera Says:

    I am having a terrible time controlling crayfish in my yard. There are probably 50 burrows and tehy are killing the grass in teh yard In addition they pose a concern for my dog if his paw gets caught in a hole while running. I live in Racine cnty a few hundred yards off the fox river. Any way to get rid of them. I have tried everything.
    Thanks
    Paul

  3. Tom Says:

    Paul,

    How do you feel about eating crayfish? Some websites suggest pouring various chemicals down their holes. Others say you should never pour any chemicals into the ground, especially not so close to wetlands. I side with the never pouring chemicals into the ground camp.

    My suggestion is to make yourself a crayfish trap out of screening and bait it with some kind of meat or fish scraps and see if you can catch enough of them to make a meal. They come out of their tunnels at night to forage, so put the trap out at night. Other than that, the report below mentions that some people believe that mixing gravel into your soil will discourage crayfish.

    http://www.usbr.gov/lc/phoenix/biology/azfish/pdf/CrayfishFinal.pdf

  4. Ask a Naturalist.com » What is a Burrowing Crayfish? Says:

    [...] They make tunnels in mud near water. You can read more about burrowing crayfish at this post: http://askanaturalist.com/burrowing-crayfish/. Share:  Print [...]

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