aves in northern Arizona and 

 western New Mexico are being researched and inventoried by 

scientists with the U.S. Geological 

Survey and cooperating agencies. 

Southwestern caves have been 

little studied, and scientists are 

now finding that these lightless 

and nutrient-poor natural systems 

are home to life forms found nowhere else on Earth. This research 

has identified unique communities 

of arthropods (insects, arachnids, 

and crustaceans) that include 3 

new genera, or groups of species, 

and at least 15 new species—

some only known to exist in a 

single cave. This exciting research 

is yielding information that will be 

used by resource managers to better understand and protect fragile 

and important Southwestern cave 

ecosystems.

C

Southwest Caves Reveal New Forms of Life

U.S. Department of the Interior

U.S. Geological Survey

USGS Fact Sheet 2009–3024

2009

Few caves in any region of the 

world have been studied at an ecosystem level, and the caves of the southern Colorado Plateau—the Four Corners region of the Southwestern United 

States—are no exception. Scientists 

from the U.S. Geological Survey 

(USGS), Northern Arizona University, 

National Park Service, and Bureau 

of Land Management have begun an 

effort to inventory and study caves in 

northern Arizona and western New 

Mexico. The research team is not only 

studying the physical environments 

found in caves but also documenting 

their biodiversity. 

When it comes to the American 

Southwest, many people think of the 

desert as the region’s ultimate challenging environment, but a Southwestern cave may be an even more 

extreme environment than the aboveground desert. Isolated from light 

A scientist explores a recently discovered cave in Grand Canyon-Parashant National Monument, Arizona. This 

desert cave is unusual because it has numerous standing pools of water. (Photograph courtesy of Jon Jasper, 

Bureau of Land Management, and Kyle Voyles, National Park Service.)

A breeding pair of cave crickets that belongs to a genus new to science. U.S. Geological Survey scientists and 

their cooperators recently discovered the crickets in Grand Canyon-Parashant National Monument, Arizona. (Photograph courtesy of Kyle Voyles, National Park Service.)

In cooperation with Northern Arizona University Merriam-Powell Center for 

Environmental Research, National Park Service, and Bureau of Land Management

and vegetation, caves are inherently 

nutrient starved and rely on inputs 

from the surface to support life underground. Cave dwellers like bats and 

crickets “import” nutrients by feeding outside of caves and returning to 

deposit guano, or feces. Guano can 

be a critical part of the food web in 

cave environments. Other nutrients 

are brought into caves when flooding 

or wind carries vegetation and other 

organic material into caves.
Not only are Southwestern caves 

nutrient poor, but also water is often 

scarce. Those subterranean pools and 

streams that do exist in caves can be 

oases for cave-adapted species.

Despite being extreme environments, caves shelter a wide range 

of life. Some cave animals such as 

bats live part of their lives outside 

of caves, and some creatures never 

leave them. For example, “troglobites” are animals that spend their 

entire lives underground and may 

include invertebrates such as spiders, 

insects, and millipedes. Aquatic troglobites called “stygobites” include 

animals such as shrimp, crayfish, and 

fish.

Cave-adapted animals have 

interesting evolutionary adaptations 

that reflect the extreme environments 

found in caves. These animals often 

lack skin pigmentation and eyes and 

have elongated appendages that help 

them to move more efficiently, thus 

conserving energy. Troglobitic invertebrates may also have longer hairs, 

or “setae,” and antennae than their 

surface counterparts that help them 

sense their surroundings in complete 

darkness.

Microbes are some of the organisms best adapted to life in caves. 

Some microbes can feed on the 

minerals found on rocks or within 

subterranean pools, and others 

even filter nutrients from the air. 

These tiny organisms can be very 

important to cave ecosystems—in 

some cases, microbes can serve as 

the center of a cave’s food web. 

To better understand and document 

cave ecosystems, scientists have 

developed an inventory protocol 

based on the most effective techniques of specimen collection and 

random sampling to better characterize cave environments.

As of March 2009, USGS 

scientists and their cooperators 

have identified 3 new invertebrate 

genera—a millipede, a cricket, and 

a barklouse—and at least 15 new 

species of arthropods from caves in 

northern Arizona.

Pools and streams in caves are 

proving to be good places to look for 

new forms of life. USGS researchers 

have found a new species of amphipod, a small shrimp-like crustacean, 

in a stream cave in Grand Canyon, 

Arizona, that is not known to exist 

anywhere else on the planet. Scientists 

may also have identified a new species 

of copepod, a small crustacean, in subterranean pools in a cave on the north 

rim of Grand Canyon. 

Cave dwellers and cave environments are proving to be fragile. For 

example, pregnant female bats congregate in the early summer at roost sites, 

known as maternity roosts, to bear 

For more information contact:

U.S. Geological Survey

Southwest Biological Science Center

Colorado Plateau Research Station

Flagstaff, Arizona

928-523-9080 or

Jut.Wynne@nau.edu

Charles_Drost@usgs.gov

This Fact Sheet and any updates to it are available 

online at http://pubs.usgs.gov/fs/2009/3024/

and raise their pups. Even seemingly 

harmless activities, such as shining 

a light into a maternity colony, may 

cause some species of bats to leave 

their roosts and abandon their pups. 

Bat populations are of special concern 

because they are in decline worldwide. 

These winged mammals are important pollinators and seed dispersers 

and help to control agricultural insect 

pests. To limit their impacts on caves, 

researchers schedule their investigations at times when bat maternity 

roosts are not in use, or they wait until 

the bats have left for the night before 

they begin work in the cave.

The discovery of new species and 

communities of organisms living in 

cave environments may help scientists 

piece together the unique natural systems that Southwestern caves support. 

New research and recent discoveries 

help to underscore the importance of 

cave ecosystems. USGS scientists 

are working cooperatively with land 

managers to develop biodiversity 

inventory and monitoring strategies 

and ways to monitor visitor impacts 

on caves. Expanding the body of 

knowledge available to land managers about cave ecosystems in the 

American Southwest is an important 

step toward conserving these fragile 

natural systems.

This tiny barklouse, measuring only 1.3 millimeters (smaller than a grain of rice), represents a new 

genus. It was recently discovered from a cave in Grand Canyon-Parashant National Monument, 

Arizona. (Photograph courtesy of Ed Mockford, Illinois State University.)

This eyeless cave-limited millipede represents 

a new genus, Pratherodesmus, and is helping 

scientists better understand cave ecosystems. 

(Photograph courtesy of Bern Szukalski, Cave 

Research Foundation.)