Fabricius, 1798 
The genus Cambarus is the second largest freshwater crayfish genus inhabiting the Northern Hemisphere, with only sixty fewer species than the genus Procambarus. Though Cambarus are varied across species, the two terminal elements that make up the male form I gonopod form ninety degree angles with the central appendage, allowing for their identification. Unlike the genus Procambarus whose first pleopod tends to have three processes at the tip, Cambarus has only one or two. Cambarus reach 17–26 mm carapace lengths in their first year, while average adult carapace length ranges from 55–62 mm.
As a genus containing nearly 100 species, Cambarus's coloration is variable. Cambarus bartonii is dark brown, while species like Cambarus pauleyi range from subtle to vibrant blues and reds. Other species are light green or grayish in color.
Most species of Cambarus are distributed along North America's eastern coast, extending from New Brunswick to northern Florida. However, the genus extends as far westward as the Rocky Mountains of Wyoming and Colorado, inhabiting a variety of freshwater environments. Devil crayfish (Cambarus diogenes) are perhaps the most widespread species in the genus, having been found in thirty states spanning approximately 2 million kilometers. Though, most species of Cambarus are not so widely distributed.
Cambarus occupy a range of freshwater environments including streams, rivers, lakes, and burrows. Burrowing species of the genus include Cambarus dubius. Cambarus also include many cave-dwelling species, both troglobites and troglophiles. While salinity and temperature changes minimally affect Cambarus, the genus has shown an intolerance to anthropogenic pollution.
Like other crayfish, Cambarus are foragers. Diets are largely plant-based, though Cambarus also consume small marine organisms like molluscs, larvae, tadpoles and amphibian eggs. Cambarus consume small rodents or birds when available. In their first year, Cambarus typically consume 1-4% of their overall body-weight each day. The genus is central to many freshwater food webs as they help maintain water quality through consumption of algae.
One of the largest crayfish genera, Cambarus includes a sizable number of vulnerable species. Cave-dwellers like Cambarus jonesi are at risk due to their lack of genetic diversity and low population count. Other species like Cambarus veteranus are at risk due to human practices like logging and mining, which increase sediment amounts in freshwater environments. Increased sediment causes these freshwater environments to be inhabitable, and Cambarus are forced to relocate as a result.
Moulting occurs among Cambarus approximately 5-10 times during their first year, and 3-5 times during subsequent years. Cambarus remain relatively inactive during periods of moulting, as the shedding of chitin exoskeletons leaves them more vulnerable to predation and injury. Many species of Cambarus continue to grow well into adulthood.
Cambarus typically mate in the early spring. Both Cambarus bartonii and Cambarus robustus only mate once during their three-year life span, with females of both carrying fewer eggs than those of the genus Orconectes.
- Subgenus Aviticambarus Hobbs, 1969
- Cambarus hamulatus (Cope, 1881)
- Cambarus jonesi Hobbs & Barr, 1960 – Alabama cave crayfish
- Cambarus laconensis Buhay & Crandall, 2009 
- Cambarus pecki (Hobbs, 1967) 
- Cambarus speleocoopi Buhay & Crandall, 2009 
- Cambarus veitchorum J. E. Cooper & M. R. Cooper, 1997 – White Spring cave crayfish
- Subgenus Cambarus Erichson, 1846
- Cambarus angularis Hobbs & R. W. Bouchard, 1994
- Cambarus bartonii (Fabricius, 1798) – Appalachian brook crayfish
- Cambarus carinirostris Hay, 1914 – rock crawfish
- Cambarus davidi J. E. Cooper, 2000 – Carolina ladle crayfish
- Cambarus eeseeohensis Thoma, 2005
- Cambarus howardi Hobbs & Hall, 1969 – Chattahoochee crayfish
- Cambarus lenati J. E. Cooper, 2000 – Broad River crayfish
- Cambarus ortmanni Williamson, 1907 – Ortmann mudbug
- Cambarus sciotensis Rhoades, 1944 – Teays River crayfish
- Subgenus Depressicambarus Hobbs, 1969
- Cambarus catagius Hobbs & Perkins, 1967 – Greensboro burrowing crayfish
- Cambarus cymatilis Hobbs, 1970
- Cambarus deweesae R. W. Bouchard & Etnier, 1979 – valley flame crayfish
- Cambarus doughertyensis Cooper & Skelton, 2003
- Cambarus englishi Hobbs & Hall, 1972
- Cambarus graysoni Faxon, 1914 – two-spot crayfish
- Cambarus halli Hobbs, 1968
- Cambarus harti Hobbs, 1981 – piedmont blue burrower
- Cambarus latimanus (Le Conte, 1856)
- Cambarus obstipus Hall, 1959
- Cambarus pyronotus R. W. Bouchard, 1978 – fireback crayfish
- Cambarus reduncus Hobbs, 1956
- Cambarus reflexus Hobbs, 1981
- Cambarus sphenoides Hobbs, 1968
- Cambarus striatus Hay, 1902 – Hay crayfish
- Cambarus strigosus Hobbs, 1981
- Cambarus truncatus Hobbs, 1981 – Oconee burrowing crayfish
- Subgenus Erebicambarus Hobbs, 1969
- Cambarus hubbsi Creaser, 1931
- Cambarus hubrichti Hobbs, 1952 – Salem cave crayfish
- Cambarus maculatus Hobbs & Pflieger, 1988 – freckled crayfish
- Cambarus ornatus Rhoades, 1944
- Cambarus rusticiformis Rhoades, 1944 – Depression crayfish
- Cambarus tenebrosus Hay, 1902 – cavespring crayfish
- Subgenus Exilicambarus Bouchard & Hobbs, 1976
- Cambarus cracens R. W. Bouchard & Hobbs, 1976
- Subgenus Glareocola Bouchard & Bouchard, 1995
- Cambarus brachydactylus Hobbs, 1953
- Cambarus friaufi Hobbs, 1953 – hairy crayfish
- Cambarus williami R. W. Bouchard & J. W. Bouchard, 1995 – Brawleys Fork crayfish
- Subgenus Hiaticambarus Hobbs, 1969
- Cambarus chasmodactylus James, 1966 – New River crayfish
- Cambarus coosawattae Hobbs, 1981 – Coosawattae crayfish
- Cambarus elkensis Jezerinac & Stocker, 1993 – Elk River crayfish
- Cambarus fasciatus Hobbs, 1981 – Etowah crayfish
- Cambarus girardianus Faxon, 1884
- Cambarus longirostris Faxon, 1885
- Cambarus longulus Girard, 1852
- Cambarus manningi Hobbs, 1981
- Cambarus speciosus Hobbs, 1981
- Subgenus Jugicambarus Hobbs, 1969
- Cambarus aculabrum Hobbs & Brown, 1987 – Benton County cave crayfish, cave crayfish
- Cambarus asperimanus Faxon, 1914
- Cambarus batchi Schuster, 1973 – bluegrass crayfish
- Cambarus bouchardi Hobbs, 1970 – Big South Fork crayfish
- Cambarus carolinus (Erichson, 1846)
- Cambarus causeyi Reimer, 1966
- Cambarus clivosus Taylor, Soucek & Organ, 2006
- Cambarus conasaugaensis Hobbs & Hobbs III, 1962
- Cambarus crinipes R. W. Bouchard, 1973
- Cambarus cryptodytes Hobbs, 1941 – Dougherty Plain cave crayfish
- Cambarus distans Rhoades, 1944 – boxclaw crawfish
- Cambarus dubius Faxon, 1884 – upland burrowing crayfish
- Cambarus gentryi Hobbs, 1970
- Cambarus jezerinaci Thoma, 2000
- Cambarus monongalensis Ortmann, 1905
- Cambarus nodosus R. W. Bouchard & Hobbs, 1976
- Cambarus obeyensis Hobbs & Shoup, 1947 – Obey crayfish
- Cambarus parvoculus Hobbs & Shoup, 1947 – mountain midget crayfish
- Cambarus setosus Faxon, 1889 – bristly cave crayfish
- Cambarus subterraneus Hobbs III, 1993 – Delaware County cave crayfish
- Cambarus tartarus Hobbs & M. R. Cooper, 1972 – Oklahoma cave crayfish
- Cambarus tuckasegee Cooper & Schofield, 2002
- Cambarus unestami Hobbs & Hall, 1969
- Cambarus zophonastes Hobbs & Bedinger, 1964 – cave crayfish, Hell Creek cave crayfish
- Subgenus Lacunicambarus Hobbs, 1969
- Cambarus diogenes Girard, 1852 – devil crawfish, devil crayfish
- Cambarus ludovicianus Faxon, 1884 – painted devil crayfish
- Cambarus miltus Fitzpatrick, 1978 – rusty grave digger
- Subgenus Puncticambarus Hobbs, 1969
- Cambarus acuminatus Faxon, 1884
- Cambarus brimleyorum Cooper, 2006
- Cambarus buntingi R. W. Bouchard, 1973 – Bunting crayfish
- Cambarus callainus Thoma, Loughman & Fetzner, 2014 
- Cambarus chaugaensis Prins & Hobbs, 1972 – Chauga crayfish
- Cambarus coosae Hobbs, 1981
- Cambarus cumberlandensis Hobbs & R. W. Bouchard, 1973 – Cumberland crayfish
- Cambarus extraneus Hagen, 1870 – Chickamauga crayfish
- Cambarus georgiae Hobbs, 1981 – Little Tennessee crayfish
- Cambarus hiwasseensis Hobbs, 1981 – Hiwassee crayfish
- Cambarus hobbsorum J. E. Cooper, 2001 – Rocky River crayfish
- Cambarus hystricosus Cooper & Cooper, 2003
- Cambarus johni Cooper, 2006
- Cambarus nerterius Hobbs, 1964 – Greenbrier cave crayfish
- Cambarus parrishi Hobbs, 1981 – Hiwassee headwater crayfish
- Cambarus reburrus Prins, 1968 – French Broad crayfish
- Cambarus robustus Girard, 1852 – big water crayfish
- Cambarus scotti Hobbs, 1981 – Chattooga crayfish
- Cambarus smilax Loughman, Simon, and Welch, 2011 – Greenbrier crayfish
- Cambarus spicatus Hobbs, 1956
- Cambarus veteranus Faxon, 1914 – Big Sandy crayfish
- Subgenus Tubericambarus Jezerinac, 1993
- Cambarus acanthura Hobbs, 1981
- Cambarus polychromatus Thoma, Jezerinac & Simon, 2005
- Cambarus thomai Jezerinac, 1993 – little brown mudbug
- Subgenus Veticambarus Hobbs, 1969
- Cambarus pristinus Hobbs, 1965 – pristine crayfish
|Wikimedia Commons has media related to Cambarus.|
- Horton H. Hobbs, Jr. (1974). "A Checklist of the North and Middle American Crayfishes (Decapoda: Astacidae and Cambaridae)" (PDF). Smithsonian Contributions to Zoology. 166 (166): 1–161. doi:10.5479/si.00810282.166.
- Longshaw, Matt (2016). Biology and Ecology of Crayfish. New York: CRC Press. pp. 17–18. ISBN 9781498767323.
- Holdich, David M. (2002). Biology of Freshwater Crayfish. London: Blackwell Science. pp. 609–613. ISBN 0-632-05431-X.
- Cordeiro, J. (2014). "Cambarus diogenes". Encyclopedia of Life. Retrieved March 29, 2018.
- Buhay, J; et al. (February 2007). "Molecular taxonomy in the dark: Evolutionary history, phylogeography, and diversity of cave crayfish in the subgenus Aviticambarus, genus Cambarus". Molecular Phylogenetics and Evolution. 42: 435–448 – via ScienceDirect.
- James W. Fetzner, Jr. (January 14, 2008). "Genus Cambarus Erichson, 1846". Crayfish Taxon Browser. Carnegie Museum of Natural History. Retrieved March 9, 2010.
- "Cambarus". Integrated Taxonomic Information System.
- "Search". IUCN Red List. IUCN. Retrieved October 7, 2010.
- Jennifer E. Buhay; Keith A. Crandall (2009). "Taxonomic revision of cave crayfish in the genus Cambarus subgenus Aviticambraus (Decapoda: Cambaridae) with descriptions of two new species, C. speleocoopi and C. laconensis, endemic to Alabama, U.S.A." (PDF). Journal of Crustacean Biology. 29 (1): 121–134. doi:10.1651/08-3089.1. Archived from the original (PDF) on 2011-07-19.
- Roger F. Thoma; Zachary J. Loughman; James W. Fetzner, Jr. (2014). "Cambarus (Puncticambarus) callainus, a new species of crayfish (Decapoda: Cambaridae) from the Big Sandy River basin in Kentucky, Virginia, and West Virginia, USA" (PDF). Zootaxa. 3900 (4): 541–554. doi:10.11646/zootaxa.3900.4.5.