NASHVILLE, Tenn. (WKRN) — Tennessee is home to 132 endangered species, ranging from birds to clams, but one tiny critter is the only one of its kind to be listed in the state.

As the U.S. Fish and Wildlife Service puts it, the spruce-fir moss spider is not a “high-profile nor high-charisma animal.” But it is the only arachnid found in Tennessee that is considered to be an endangered species, and one of few endangered spiders in the United States.

Most people would never know if they saw it as the spider is about the size of a pencil eraser. Despite its tiny size, the spruce-fir moss spider is actually classified as a tarantula, and according to the National Parks Conservation Association (NPCA), it’s one of the smallest in the world.

It is typically found in high-elevation forests of Fraser fir and red spruce, like those in eastern Tennessee, and is one of many protected species at Great Smoky Mountains National Park.

Spruce-fir moss spider in hand. (Courtesy: U.S. Fish and Wildlife Service)

The spider was first discovered atop North Carolina’s Mount Mitchell in 1923, according to the National Wildlife Federation (NWS). But because of its small size and concealed habitat, there is still little known about its habits.

When the spruce-fir moss spider was listed as endangered in 1995, the NPCA said there were only five known populations on three mountain ranges in western North Carolina and eastern Tennessee.

The decision to list the spider as an endangered species under the Endangered Species Act of 1973 was made based on several factors, according to the FWS. At the time, it was just one of three listed spiders in the U.S.

Around the turn of the 20th century, several of the forests the spider relies on experienced industrial-scale logging, followed by catastrophic wildfires. Much of that area is now protected from habitat degradation, but the FWS said other factors continue to impact the species.

In recent decades, those same forests have suffered from acid precipitation and the arrival of an invasive insect called the Balsam woolly adelgid.

The insect, which has no natural enemies in North America, attacks and kills the spruce-fir moss where the spider creates its tube-shaped webs. The result is often deadly for the trees as well.

According to a 2014 FWS review on the spruce-fir moss spider, 95% of the Southern Appalachians’ mature Fraser firs have died because of the adelgid.

Changes in forest climate and moisture have also limited the spider’s habitat, and its already low population numbers increase its vulnerability to threats, the NPCA reported.

Spiders play an important role in the regulation of insect populations, and the FWS reports that if one species disappears — even if it’s as small as the spruce-fir moss spider, which feeds on mites and springtails — its absence can have an impact on ecosystems.

Spider venom from tarantulas like the spruce-fir moss spider is also being researched as a possible treatment for preventing brain damage in stroke patients and some diseases like Alzheimer’s, according to the FWS.

Today, the tiny tarantula’s entire known global distribution consists of less than 25 mountain tops spread across Virginia, North Carolina and Tennessee. However, efforts to protect the spruce-fir moss spider are ongoing.

In addition to chemically treating infected trees and playing an active role in the Southern Appalachian Spruce Restoration Initiative, a multi-organizational partnership aimed at expanding red spruce forests, researchers are working to better understand the species.

By determining the spider’s life history and habitat needs, the NPCA said biologists will be able to learn more ways to help the population grow. The ultimate recovery goal is to have six distinct populations within the spider’s historic habitat range.