Cave Inhabitants of Oregon

By Matt Skeels

Last updated: 2023.03.15

This quick reference guide describes commonly encountered cave fauna, as well as a few rare species found throughout Oregon. It is divided into three categories: Trogloxenes, Troglophiles, and Troglobites. The topic of bats is expansive so be check out our separate article for more information. Special thanks and credit go to the photo contributors: Brent McGregor for the bulk of the photos, Kim Luper for the pika, and others where noted.

Trogloxenes

This group of cave fauna is classified as anything that lives near a cave, in the entrance of a cave, or cannot live its entire life within a cave. This is the most expansive group, and many will, at one time or another, wander into a cave, or utilize a cave entrance. This list is so large that many trogloxenes are absent from this article, including domestic cats, bears, cougars, bobcats, coyotes, porcupines, skunks, chipmunks, rabbits, squirrels, bats, snakes, birds (pigeons, swallows), spiders, beetles, flies, slugs, snails, scorpions, millipedes, and more. What follows are pictures of some of the more common and unique species.

Tissue Moth or Triphosa haesitata

Tissue Moths are probably the most common of all cave life in Oregon and encountered in nearly every Oregon cave. As a caterpillar, they live entirely outside of caves. After becoming a moth, they seek safe environments, such as caves where they will often huddle in clusters on cave walls or ceilings. You will often discover their leftover wings, usually a sign of predation by bats.

Harvestman or Daddy-Long Legs or Sabacon occidentalis

The common Harvestman will hide in dark places, such as a basement, or even a cave. Harvestman are common throughout most Oregon environments. Typically, Harvestman will live near a cave entrance and feed on other insects, or they will exit to feed. The above photo was taken from outside of a cave. Notice the lack of black pincers when compared to Taracus marchingtoni (see below).

Cave Cricket or Camel Cricket or Tropidischia xanthostoma

Cave crickets are somewhat common in Central Oregon, but more commonly in the humid and nutrition-rich environments west of the Cascades. The crickets can be found in many locations, but prefer a cave environment when available. They can grow very large (up to 8 inches), accentuated by long antennae and powerful back legs. Like most insects, they will cling to a walls or the ceiling. This cricket was photographed at Incline Cave.

Springtail or Pogonognathellus celsus

Sometimes generally referred by its scientific name Collembola, springtails are small, wingless insects, most of which have the ability to hop relatively long distances. The springtails of Central Oregon usually have a silver-like coloring. Springtails usually feed on microorganisms or detritus. In Central Oregon caves, springtails have been observed in detritus originating from woodrat debris, or fecal matter. Photo is of Pogonognathellus flavescens of Great Britain.

Pika or Ochotana princeps

Pika are skittish cave inhabitants. More often than not, a pika is heard but never seen. Their telltale sound "Eeeeep!" is high-pitched and often muffled as it emanates from behind rocks. You may also see their distinctly round fecal pellets, or sometimes their little nests. Pika may be briefly seen at a cave entrance or inside a cave before they dart inside for protection. They are most often encountered at higher elevations and prefer mountainous terrain. The tail of a pika is very short like a hamster. Pictured here is a rare shot of a pika taken by Kim Luper from a cave in Washington.

Woodrat or Packrat or Neotoma cinerea

Pictured here is a bushy-tailed woodrat. The bushy-tailed woodrat is one of three woodrats found in Oregon. They are more adaptable to different environments than a pika and not as skittish. While still prone to hiding, on occasion they'll come out for a peek, or crawl along a cave ceiling or wall while you are exploring. Their nests are commonly seen in many caves and have a round bowl-like shape inside a mound of dead grass, usually at the terminus of a cave, or just inside the entrance. In Central Oregon, woodrats will often collect juniper branches, twigs, and mushrooms to last the winter months during hibernation. The other two species known to exist in Oregon are the desert woodrat (Neotoma Lepida) and the dusky-footed woodrat (Neotoma fuscipes).

Tree frogs & Toads

Tree frogs and toads are common in the caves of Central Oregon and elsewhere. They usually live near the entrance and feeding opportunistically. Also quite common, tree frogs trapped in a cave and cannot escape, such as in a pit. It's not uncommon to find them emaciated or dead.

Salamanders

In Central Oregon, salamanders are very rare because the climate is too arid. The closer you get to the Cascade mountains the better your chances are of spotting a salamander in a cave. Salamanders are typically found in Central Oregon caves when they've fallen into an inescapable entrance. In Western Oregon, salamanders are more likely to be trogloxenes, moving in and out of caves, and sometimes travel further into a cave if it's moist and food remains plentiful.

Troglophiles

A group of any species that lives its entire life in a cave, but may also just as easily live on the surface. Perhaps the most common group is mycelium which form mushrooms.

Mycelium / Fungi 

Mycelium is the organism that mushrooms grow from (top left photo). It appears as a root-like membrane that grows in the soil, but can be observed on the surface of a dirt floor in caves. Mycelium is identified by its dendritic characteristics. The number of mycelium species is too great to summarize in any detail here, but a few caves in Central Oregon grow fruiting bodies, the mushroom, at different times of the year. Mushrooms have been observed on rotting logs in cave entrances, dirt floors, or even on pinecones that have been carried in by woodrats. Because mycellium doesn't need sunlight to grow, it can carry on indefinitely within a cave, as long as nutrients remain. However, mycelium is not noted to be cave adapted.

Several different types of mushrooms have been observed in Central Oregon caves, including morels, russulas, and ubiquitous LBMs (Little Brown Mushrooms). Morels observed in caves often fruit out of season, usually a month or two delayed. The tissue moth photo above, is infected with an unknown fungus in Honeycomb Cave (photo by Matt Skeels). The blue-green gelatin-like mold (top right photo) was observed in Jaws Cave (photo by Matt Skeels). The species growing on the pinecone is Strobiluus trullisatus.

Campodean or Twintail

Another Central Oregon species found is the Campodean, sometimes referred as Diplura. It's an arthopod, and the Central Oregon species have not been identified. William Shear of Hampton-Syndey College believes they are a new species. They have been observed living alongside cave-adapted millipedes as well as caves harboring ice. Campodeans can also be found in small cracks of surface rocks, also called microcaverns. This campodean was photographed in Alpine Ranch Cave.

Cave-adapted Millipede or Plumatyla humerosa

These millipedes are likely Plumatyla humerosa, but genetic identification is required to determine if they are a new species. They predominantly inhabit lava tubes of Central Oregon as well as caves of Western Oregon. They may also inhabit small cracks in surface rock, sometimes referred to as microcaverns. These millipedes are common where mold or bat feces is scattered on the cave floor. This species has been studied and collected by Neil Marchington of the Oregon High Desert Grotto.

Grylloblattid or Grylloblatta sculleni

The Grylloblattid, uncommonly referred to as the cockroach cricket or ice crawler, is a primitive wingless insect that was much more common during the mid-Cenozoic. They flourish in cold temperatures ranging from 26.6° to 41°F and with high humidity. The grylloblattid pictured was observed May 2012 in a cave that historically harbors ice. Grylloblattids prefer ice and snow and are nocturnal. They have an omnivorous diet but primarily feed on dead arthropods and carrion. When that isn't available they will eat detritus. Their closest living relative is the Mantophasmatidae from Africa.

Troglobites (sometimes known as Troglodytes)

A Troglobite is any species adapted to live in a cave and cannot survive outside of the cave. Adaptations may vary, but most common is a loss of pigmentation making the species look white or translucent. Another adaptation are eyes that may be reduced in size or the completely absent. Other changes may include giantism, slower metabolism, or elongated appendages. Most notably, this occurs in fish, salamanders, and crayfish, but Oregon lacks these types of troglobites. In Oregon all troglobites are invertebrates. Neil Marchington of the Oregon High Desert Grotto has worked with the Deschutes National Forest and Bureau of Land Management, among others, to help discover new troglobitic species. The Taracus marchingtoni has been named after him and first identified in 2008. In 2012, the Trogloraptor was declared as a new species of spider and Neil Marchington played a role in its discovery.

Taracus marchingtoni

This species of harvestman has been found in 18 different caves of Central Oregon and likely exists in many more. It was observed in the past at several caves, including Lava River Cave prior to 1982, and again in 2008. Oregon High Desert Grotto member Neil Marchington was the first to study the harvestman and submitted it to Dr. William Shear of Hampton-Syndney College for identification. Shear classified it a new species endemic to Oregon. Marchington has observed the harvestman feeding on cave-adapted millipedes (see above). It utilizes its long pincers (in black) to grab prey. The picture on the left was taken in Pucker River Cave in November of 2012.

Trogloraptor or Trogloraptor marchingtoni

As a cave or spider lover, you may have heard of the recent discovery of the Troloraptor that made the news in 2012. With the help of Geo Graening, Neil Marchington, Ron Davis, and Daniel Snyder, the spider was observed in southwestern Oregon caves, and a few specimens were submitted to Charles Griswold, Traci Audisio, and Joel Ledford. Audisio named the spider after Neil Marchington for helping out the arachnologists.

The spider traps prey, by constructing small webs made up of only a few strands, Although its main prey remains unknown. Trogloraptor has six eyes, is yellow-brown in color, and has hook-like claws at the ends of its legs. A mature spider is roughly about a third of an inch long. 

Mite or Rhagidiidae (possibly Flabellorhagidia pecki)

Mite species, possibly Flabellorhagidia pecki, of the Rhagidiidae family. The length is between 1 and 2 millimeters. Its legs have tinyl bristles. The most important feature of this specimen is the white color. This is a good indicator, though not definitive, of cave adaptation. The specimen on the right was observed in Talking Scroll Cave of Central Oregon in 2012. Special thanks to Francis G. Howarth for the identification. First photo was taken courtesy of Andrew Quick.

Pseudoscorpions

Photographed in No Name Cave, this picture shows their similarity to real scorpions but lack stinger tails. This species is currently unidentified.

Parobisium charlotteae

Central Oregon had a new species of pseudoscorpion collected in 1938 by J. Valentine at the Redmond Caves. Joseph Chamberlin identified and named it Parobisium charlotteae after his wife. Charlotteae are now thought to be extirpated from the Redmond Caves. In 2013, a group from the Oregon High Desert Grotto collected a pseudoscorpion in an unrelated cave of Central Oregon that appears to be charlotteae. If so, this would be an exciting rediscovery. Pictured here is the specimen collected in 2013.

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