More than three thousand caves lie under Texas Hill. Today, scientists and cavers have explored and mapped most of them. This was not the case in the late 1950s, when James Reddell, an English specialist at the University of Texas, joined the school’s caving society and began crawling into caves after school and on weekends. He enjoyed climbing and gliding through narrow passages and labyrinthine tunnels using only the light of his headlamp, but what really thrilled him was being able to see places and creatures that were virtually unknown. While explorers have been mapping the land in Texas for centuries, collecting and identifying plants and animals on the surface, the caves were essentially a blank slate. Reddell was fascinated by these hidden worlds and took every opportunity to explore the caves of Texas and Mexico. He eventually turned his passion into a career when he became the cave invertebrate curator for the UT Insect Collection, and for a time he was probably the only cave biologist in Texas.
Riddell had no shortage of interesting species to explore. Cave creatures, also known as troglobites (not to be confused with their more adaptable relatives, troglophiles), are extremely strange. While some of these creatures are fish and amphibians, most are spiders, crustaceans, and other small, running invertebrates. In order to live in complete darkness and without food, they had to develop some rather strange traits. Most troglobites are blind, pale, and slow. Some of these picky, hypersensitive species are so specialized that they cannot survive outside a particular cave, let alone sunlight. They are the introverts of the underworld.
Over the course of several decades, Reddell collected the creatures he found in the caves, cataloged them, and occasionally sent them to others for study and identification, slowly sorting the mysterious creatures into families and genera and giving them names. “We just look everywhere in the cave, turn over the rocks and look at the walls, the floor and the ceiling, at the pools,” says Reddell. “We take everything we can, put it in vials or jars, and bring it back to the lab to sort it out and send it to the experts.” Reddell, now in his 80s, has spent decades collecting tens of thousands of critters from more than a thousand caves in Texas and hundreds more in Mexico, New Mexico and California.
Thanks in part to Reddell and his colleagues’ years of work underground, many of the species Reddell helped identify are now on the federal endangered species list. In fact, of the eleven endangered arachnids in the United States, nine are found only in Texas. These creepy crawlers live in the caves of Central Texas within the Balcone Escarpment, a narrow fault zone that runs along the eastern edge of the Edwards Plateau, where wooded hills drop into the coastal plains.
One of the rare species that Reddell first discovered in the 1960s is a blind, long-legged arachnid called the bonecave reaper. In recent years, this little creature has been at the center of a big controversy that almost reached the US Supreme Court and threatened not only this particular creature, but 70 percent of all endangered animals protected under the Endangered Species Act. . On December 28, the saga ended with a rare victory for environmentalists: the US Fish and Wildlife Service announced that the Bone Cave harvester will remain on the list of endangered species.
We’ll get into politics in a moment, but first, what the hell is a Bone Cave reaper? It looks a lot like a spider, but it’s not. The peppercorn-sized creature (it reaches 0.1 inches in length) is a light orange version of the long-legged daddies you’ve likely seen above ground. (“Daddy long-legged” is a nickname for Harvestmen, emphasizing their extremely long appendages, which are well adapted for moving quickly along cave walls.) While spiders have separate heads, Harvestmen are distinguished mainly by their single fused head and body. Reapers also do not have poison glands and spinnerets for weaving webs.
The Bone Cave Reaper lives only in subterranean habitats, mostly in narrow crevices and under rocks, although it is occasionally seen running across the floor or wall of the cave. Because it is so rare and only found underground, relatively little is known about this species. It is likely that, like other harvesters, he is both a scavenger and a predator. It can feed on decaying organic matter, grubs, and even smaller cave critters such as springtails. Similarly, harvesters are likely food for cave spiders, scorpions, and centipedes. An individual can live up to four years, or maybe longer.
The Bone Cave Reaper probably lived in Texas before the last Ice Age. Experts suspect that two different species descended from a common ancestor and roamed the earth before climate change drove them underground. Research shows that critters in the northernmost part of their range, in Williamson County, most likely went underground earlier and more fully adapted to cave life, developing longer legs and lighter pigmentation. When the Colorado River cut through the geological layers in Central Texas, it likely created a barrier and the two species adapted to cave life at different rates on either side. Today, the Bone Cave Reaper lives north of the river, while his cousin, the Bee Creek Cave Reaper, lives south of the river.
Until the early nineties, these and several other different arachnids were considered the same species: Texella Reddelli. The name is a tribute to Reddell, the fearless Texan who first collected animals. (There are now 51 species named after him.) In 1992, Darrell Ubik and Thomas Briggs, taxonomists at the California Academy of Sciences, examined the harvestmen that Reddell and his team had collected and found that what had previously been thought to be a single species was in fact more. Thanks to their painstaking work, the haymaker from Kostyanaya Cave was identified as a separate species for the first time. The common name refers to where Reddell and his team found the creature. Its scientific name Texella Reyesi, after Marcelino Reyes, Riddell’s longtime assistant and caving buddy. He was part of the team that collected the specimen from Bone Cave in Williamson County.
Now we come to the political part of the story. In 1988, when development and population growth led to habitat loss in Central Texas, the USFWS added the harvesthorn to its list of endangered species. Since then, a dizzying array of bureaucratic and legal efforts have been made to strip the humble invertebrate of its federal protection. It’s not because someone has a vendetta against the harvester – although his lack of charisma certainly doesn’t help – but rather because growing around an endangered species is a pain. For example, if you want to build houses or commercial buildings on your land, you will have to dig the ground to build a foundation, and doing so or laying paving slabs on a once-permeable green area in the wrong place can disrupt the fragile ecosystem in which these animals thrive. Compliance with the law could mean more bureaucracy for landowners, although the Endangered Species Act does not ban development near a harvester’s habitat. “It’s a misconception that once a species is listed, it stops its development,” says Michael Warriner, an observer biologist at the USFWS. “There are a number of opportunities for someone to still develop real estate.” However, landowners who knowingly disturb an endangered habitat can be subject to severe fines or even jail time.
In 1993, a Williamson County judge filed the first motion to delist the haymaker and six other invertebrates. Then, in 2014, a group that included Georgetown property owners and a conservative private property rights organization petitioned the USFWS to delist the species. Initially, the agency held firm, but the applicants took the case to federal district court, where a judge ruled that the agency needed to revisit its list of endangered species. Texas Attorney General Ken Paxton welcomed the decision, saying “the court’s decision is a victory for private property rights in Texas and a defeat for land grabbing in the Obama era.” In 2019, under the Trump administration, the USFWS reversed course, decided that exclusion of the harvester from Bone Cave could be justified, and initiated a more detailed review.
The state’s most influential right-wing think tank then joined the fray. The Texas Public Policy Foundation launched a constitutional challenge (ardently supported by Paxton) to the Endangered Species Act. The TPPF argued that the federal government did not have the authority to protect the haymaker because it is only found in Texas. Now the dispute was not only about the harvester, but also about 70 percent of endangered species found in just one state. All of them can lose their protection in the event of a TPPF victory. The debate went on in the courts for more than five years, and in the end, environmentalists won. The District Court dismissed the constitutional suit, the Fifth Circuit dismissed the appeal, and in 2021 the U.S. Supreme Court declined to hear the case. “We are glad that this attack on the constitutionality of the Endangered Species Act will not go any further,” a lawyer for the Center for Biological Diversity said at the time. The recent decision to keep the endangered status may have finally solved the problem, at least for now.
Riddell was not surprised by the decision, but welcomed it. Many of the caves he explored back in the sixties were completely destroyed as urban sprawl spread beyond Austin. “If it wasn’t for the Endangered Species Act, there wouldn’t be so many caves left in Central Texas,” he says. In fact, the bone cave mower and its relatives may be one of the few obstacles still standing in the way of the widespread destruction of cave ecosystems and the green spaces above them.
“People say, ‘Why are we worrying about all these bugs?’ Well, the thing is, we’re worried about our lifestyle, says Riddell. “You can’t tell me that a developer will go broke because he set aside a few acres for bugs.”