A Year of Native Animals: the Virile Crayfish

In 2026, Friends of the Chicago River invited people across the Chicago-Calumet River system to make Wild River Resolutions, a yearlong reminder to discover, celebrate, and protect the wildlife that depends on a healthy river. Throughout the year, we are highlighting 12 native animals, one each month, that call the 156-mile river system home.

Designed to both educate and inspire, Wild River Resolutions connects people to the species living in and along the river while spotlighting simple, everyday actions that support a healthy, biodiverse, and accessible river system for all people, water, and wildlife.

 May – Virile crayfish (Faxonius virilis)

Quite common in the Chicago-Calumet River system, virile crayfish are native to the Great Lakes region and across many northern states. The virile crayfish is also the ambassador species featured on this year’s Chicago River Day t-shirt. It lives in rivers, lakes, ponds and streams that do not freeze solid, and need rocks and vegetation to hide from predators and overwinter.

Virile crayfish have brown to reddish brown bodies, are between 10-12 cm long and have a variety of leg types. Their front most legs are the two chelipeds, or large claws, which are a bluish color, and males typically have larger claws than females. After the claws there are four pairs of jointed legs known as pereiopeds which are used for walking, gathering food, and to hold the reproductive organs of virile crayfish. Next are five pairs of special legs used for swimming known as swimmerets or pleopods. Friends’ restoration projects have improved water quality for crayfish and their diet of plants and animals.

Read more about the virile crayfish in the spring-summer edition of the River Reporter.