Tiny Crayfish

Tiny Crayfish from the Wetland, 3/15/21

"Crawdads" is what we called them where I was growing up, but they have many other interesting regional names as well. Scientists recognize some 600 species of crayfish worldwide, of which 375 are found in the United States and 23 in Illinois. Like the fairy shrimp and the isopods, crayfish are crustaceans. The family resemblance to lobsters is unmistakable, though lobsters strictly inhabit saltwater environments and crayfish freshwater.

This little guy is no doubt newly hatched this spring. Crayfish have an interesting technique for caring for their young. Female crayfish "cement" their fertilized eggs under their tails and when they hatch, the young continue to cling there until after their first three moults when they are big enough to fend for themselves.  The photo at the bottom of the page was taken at Homer Lake this Spring, though at a different temporary wetland, a flooded field in the middle of the woods which I found by following the frog calls. If you look closely, you can see baby crayfish bunched up and tucked in under mama's tail -- click the photo to enlarge it and they are more visible on the right side).

The many species of crayfish live in a variety of freshwater habitats. As always, the survival of a strictly aquatic species in a temporary pond presents a puzzle to be solved. Many crayfish species, including this one, the prairie crayfish, are adept at digging burrows down to the groundwater level and surviving there. Some species in fact live almost exclusively in their burrows and emerge only for feeding or reproduction. As with many other animals that modify their habitats and construct homes -- I'm thinking for example of woodpeckers or the master builders, beavers -- crayfish burrows come in handy for many other creatures as well. For example, the Kirtland watersnake and the Massasauga rattlesnake (neither species present at Homer Lake) both overwinter in crayfish burrows, and crayfish burrows provide refuge for some species of dragonflies before they transform into the flying marvels we know so well.

Crayfish feed on a variety of things: plant, animal, living and dead, and are in turn an important food source for many other species, humans included! (no crayfish were eaten in the writing of this blog post)

For more on crayfish, the following resources have been helpful for me:


Female Crayfish with Young Under Her Tail, 2/28/21


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