The Kentucky cave shrimp, Palaemonias ganteri, is an eyeless, troglobite

Troglobite

Troglobites are small cave-dwelling animals that have adapted to their dark surroundings. Troglobite species include spiders, insects, fish and others. They live permanently underground and cannot survive outside the cave environment. Troglobite adaptations and characteristics include a heightened...

 shrimp

Shrimp

Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...

. It lives in cave

Cave

A cave or cavern is a natural underground space large enough for a human to enter. The term applies to natural cavities some part of which is in total darkness. The word cave also includes smaller spaces like rock shelters, sea caves, and grottos.Speleology is the science of exploration and study...

s in Barren County

Barren County, Kentucky

As of the census of 2000, there were 38,033 people, 15,346 households, and 10,941 families residing in the county. The population density was . There were 17,095 housing units at an average density of...

, Edmonson County

Edmonson County, Kentucky

Edmonson County is a county located in the U.S. state of Kentucky. It was formed in 1826. As of 2007, the population was 11,978. It is included in the Bowling Green Metropolitan Statistical Area. Its county seat is Brownsville...

, Hart County

Hart County, Kentucky

Hart County is a county located in the U.S. state — or, more correctly, "Commonwealth" — of Kentucky. It was formed in 1819. , the population was 17,445. Its county seat is Munfordville. The county is named for Captain Nathaniel G. S. Hart, a Kentucky militia officer in the War of 1812...

 and Warren County

Warren County, Kentucky

Warren County is a county located in the U.S. state of Kentucky, specifically the Pennyroyal Plateau and Western Coal Fields regions. It is included in the Bowling Green, Kentucky, Metropolitan Statistical Area. The population was 113,792 in the 2010 Census. The county seat is Bowling Green...

, Kentucky

Kentucky

The Commonwealth of Kentucky is a state located in the East Central United States of America. As classified by the United States Census Bureau, Kentucky is a Southern state, more specifically in the East South Central region. Kentucky is one of four U.S. states constituted as a commonwealth...

. The shrimp's shell has no pigment

Pigment

A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...

; the species is nearly transparent and closely resembles its nearest relative, the Alabama cave shrimp

Alabama cave shrimp

The Alabama cave shrimp, Palaemonias alabamae, is a species of shrimp in the family Atyidae, found only in caves in the state of Alabama.-Conservation status:...

.

The habitat of the Kentucky cave shrimp is exclusively in underground streams of caves. It is endemic to the Mammoth Cave National Park

Mammoth Cave National Park

Mammoth Cave National Park is a U.S. National Park in central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. The official name of the system is the Mammoth-Flint Ridge Cave System for the ridge under which the cave has formed. The park was established...

 region of central Kentucky. The shrimp feeds mainly on sediment

Sediment

Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....

s that are washed into the cave by the movement of groundwater

Groundwater

Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...

.

The Kentucky cave shrimp was registered as an endangered species

Endangered species

An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...

 under the Endangered Species Act

Endangered Species Act

The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...

 in 1983, and was included on the IUCN Red List

IUCN Red List

The IUCN Red List of Threatened Species , founded in 1963, is the world's most comprehensive inventory of the global conservation status of biological species. The International Union for Conservation of Nature is the world's main authority on the conservation status of species...

 as Endangered in 1994. It is mostly threatened by contaminated groundwater

Water pollution

Water pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....

 running into its habitat. Several nearby communities either have inadequate sewage treatment

Sewage treatment

Sewage treatment, or domestic wastewater treatment, is the process of removing contaminants from wastewater and household sewage, both runoff and domestic. It includes physical, chemical, and biological processes to remove physical, chemical and biological contaminants...

 facilities or lack such facilities altogether. An additional potential threat is the entry of contaminants from traffic accidents and roadside businesses. One incident in 1979 caused the death of aquatic cave organisms in a part of the Mammoth Cave system, and in a 1980 incident, a truck carrying toxic cyanide

Cyanide

A cyanide is a chemical compound that contains the cyano group, -C≡N, which consists of a carbon atom triple-bonded to a nitrogen atom. Cyanides most commonly refer to salts of the anion CN−. Most cyanides are highly toxic....

 salts overturned on Interstate 65

Interstate 65

Interstate 65 is a major Interstate Highway in the United States. The southern terminus is located at an intersection with Interstate 10 in Mobile, Alabama, and its northern terminus is at an interchange with Interstate 90 , U.S. Route 12, and U.S...

, just south of Mammoth Cave National Park

Mammoth Cave National Park

Mammoth Cave National Park is a U.S. National Park in central Kentucky, encompassing portions of Mammoth Cave, the longest cave system known in the world. The official name of the system is the Mammoth-Flint Ridge Cave System for the ridge under which the cave has formed. The park was established...

.