Skip to Main Content

Unexpected Plants and Animals of Indiana: Hoosier Cavefish

The Empire State Building, the Pentagon, the National Cathedral and Yankee Stadium: these historic landmarks were all constructed with limestone from Monroe and Lawrence counties in Indiana. The consistent and chemically pure sedimentary rock helped Bedford earn its reputation as “The Limestone Capital of the World.” However, humans are not the only creatures that enjoy structures created from Southern Indiana’s limestone. 

Bedford’s Bluespring Caverns house more than 20 different animal species, a rare level of subterranean biodiversity. The area’s limestone caves also host the longest navigable underground river in the United States. A new and endangered species, the Hoosier cavefish (Amblyopsis hoosieri), lives in the river and its tributaries. 

Hoosier Cavefish Hoosier Cavefish, supplied by Brant Fisher, IDNR

“Hoosier cavefish have a lifespan of 15-to-20 years,” shared Lawrence County Extension educator Ophelia Davis. “To live that long underground with no sunlight, they had to make some significant adaptations.” 

Without sunlight, cavefish have no need for pigmentation. When exposed to light, their blood’s hemoglobin gives them a light pink color. Also, like most other cavefish, Hoosier cavefish lack developed eyes. 

“The other senses of cavefish are heightened to help them since they can’t see, similar to when a human loses a sense,” explained Davis. 

Cavefish compensate for their lack of sight with increased sensitivity to vibrations. Their bumpy rows of sensory papillae help them navigate through the darkness. 

Because the temperature of a cave rarely fluctuates more than a degree, cavefish do not need to adjust to variations in heat.

Food scarcity can be problematic for cavefish so they have developed a low metabolic rate. If needed, their fat reserves can sustain them for long periods between meals. Despite only averaging a few inches in length, Hoosier cavefish are the apex predator in their subterranean food chain. They mainly eat small crustaceans. 

The Hoosier cavefish was first described in 2014, making it the first new species of amblyopsid cavefish discovered in 40 years. Until then, Hoosier cavefish were thought to be the same as the Northern cavefish (Amblyopsis spelaea) found in Kentucky’s caves. Recent research proved that Hoosier cavefish above the Ohio River are different than their neighbors to the south. Though they look similar, studies showed there are genetic differences between the two and that Hoosier cavefish tend to have more robust bodies. 

“You don’t often think about the miles of caves right below your feet when you are in Lawrence County, but there is a whole ecosystem full of living organisms,” said Davis. “There is a whole world to learn about and explore.”

Food scarcity can be problematic for cavefish so they have developed a low metabolic rate. If needed, their fat reserves can sustain them for long periods between meals. Despite only averaging a few inches in length, Hoosier cavefish are the apex predator in their subterranean food chain. They mainly eat small crustaceans. 

The Hoosier cavefish was first described in 2014, making it the first new species of amblyopsid cavefish discovered in 40 years. Until then, Hoosier cavefish were thought to be the same as the Northern cavefish (Amblyopsis spelaea) found in Kentucky’s caves. Recent research proved that Hoosier cavefish above the Ohio River are different than their neighbors to the south. Though they look similar, studies showed there are genetic differences between the two and that Hoosier cavefish tend to have more robust bodies. 

“You don’t often think about the miles of caves right below your feet when you are in Lawrence County, but there is a whole ecosystem full of living organisms,” said Davis. “There is a whole world to learn about and explore.”

Featured Stories

Dog outdoors drinking water
Keeping your pets safe during the dog days of summer

As temperatures and humidity rise across the U.S., Candace Croney, director of the Center for...

Read More
Eastern hellbender salamanders feeding on bloodworms in their raceway at the Purdue Hellbender the Hellbender lab.
Metazoa Beer to Benefit Help the Hellbender Lab

Metazoa Brewing Company and the Indiana Lakes Management Society have teamed up to collaborate on...

Read More
Sonling Fei in front of digital trees
Digital forestry can help mitigate and prevent wildfires

The National Interagency Fire Center reports that, as of this writing, 19,444 fires have burned...

Read More
tomas hook next to boat
What you can do this summer to reduce the spread of aquatic invasive species

In 2020, an alligator was captured in a lagoon of Chicago’s Humbolt Park. The reptile out...

Read More
Researcher uses pipette on parsley plant
Researchers examine nanotechnological methods for improving agriculture

Nanoscale particles could potentially help address agricultural and environmental sustainability...

Read More
Fairgoers ride a tractor, sponsored by the Indiana Soybean Alliance, and browse food tents during the 2023 Indiana State Fair. (Purdue Agricultural Communications photo)
Purdue Extension to present engaging art and nature demonstrations at Indiana State Fair

The Indiana State Fair kicks off Aug. 2 and highlights the theme “The Art & Nature of...

Read More
To Top