Animals

The diversity of habitats in the park, including permanent flowing water at Rattlesnake Springs, provides for an exciting array of wildlife. This diversity is further benefited by the position of the park at the intersection of the southern Rocky Mountain, northern Chihuahuan Desert, and southwestern Great Plains biogeographic provinces.

Many animals occur here at the geographic limits of their ranges. For example, several species of reptiles are at the edges of their distributions.

The deserts of the Southwest contain some of the highest diversity of mammals, birds, reptiles, and insects in the United States. The park provides important year-round habitat for top predators such as cougars, and nesting habitat for migratory species such as the large colonies of cave swallows and Brazilian (Mexican) free-tailed bats that raise their young in Carlsbad Cavern.

Rattlesnake Springs, a rare desert wooded riparian area that has been designated an Important Bird Area (IBA) by the National Audubon Society, draws birders from around the world to see some of the 300-plus species that have been noted there. The Carlsbad Cavern Natural Entrance is also an Audubon IBA because of the large colony of cave swallows that resides and breeds there in the summer.

Birds

The list of birds that have been observed in the park includes a whopping 357 species. This huge list includes species that are year-round residents and nest here, neotropical migrants that nest in the park or pass through on the way to northern breeding grounds, winter residents, and occasional or rare species who wander in and may stay a while.

The park's common year-round residents include some interesting and colorful species. The ladder-backed woodpecker, the second-smallest North American woodpecker, is equally at home on a cactus stem or a sotol stalk as on a tree trunk—a useful adaptation when you live in desert shrublands with few trees. In fact, it was historically called cactus woodpecker. The cactus wren is another year-round resident that is obviously at home with cacti, building nests in them for breeding as well as for roosting. This is the largest of the nine North American wren species, all of which have been seen in the park and six of which breed here. Rock wrens, black-throated sparrows, and northern mockingbirds are among the commonly seen year-round residents of the park.

Migratory species are numerous. The park provides some of New Mexico's prime breeding habitat for three state-threatened birds: Bell's vireo, gray vireo, and varied bunting. Bell's vireos nest at Rattlesnake Springs, the park's wooded riparian area, while gray vireos nest in dry canyons with small desert trees such as oaks and junipers. Varied buntings nest in dry canyons with somewhat larger trees.

Amphibians

Among the park's nine amphibians are two species of spadefoot toads, Couch's spadefoot and New Mexico spadefoot. The spadefoot toads are not true toads, but belong to the primitive family Pelobatidae. Spadefoots resemble true toads (family Bufonidae) in body form, but have smoother, thinner skin. The spadefoots are named for their large, sharp metatarsal tubercles that are used to dig backwards to depths of several feet.

Spadefoots are truly adapted to life in a desert, taking advantage of the short-lived ponds created by summer thunderstorms in order to breed. It is believed that sound or vibration, such as might be caused by rainfall, cues the spadefoots to emerge from underground and congregate at the ponds. Males engage in loud choruses to attract females and rush the breeding process before the ponds disappear. Spadefoots breed quickly in order to take advantage of favorable breeding conditions and to allow the eggs and larvae as much time as possible to develop.

The park's list also includes four species of true toads (family Bufonidae); as well as a cricket frog (believed to have been extirpated from the park in recent years) and two species of true frogs, the Rio Grande leopard frog and the non-native American bullfrog.

Mollusks

Mollusks can be found in nearly every ecosystem on earth, so it's not surprising to find them in Carlsbad Caverns National Park. In much of the American Southwest, isolation of suitable habitats often results in unique, localized species. Mountain ranges with increased moisture and isolated by vast stretches of desert have turned up different species. In isolated springs, the same process can be demonstrated as the original range of a species shrinks as an area becomes more arid. This can continue until a formerly widespread species is now limited to small springs, often isolated from the nearest population by many miles. For example, the snail called ovate vertigo is a very common fossil throughout much of the Southwest, but today exists at only a few locations. It is known only in this park from unoccupied shells found at Rattlesnake Springs. The nearest population is several miles away at another spring.

The body of a mollusk is generally composed of the shell and the fleshy, living part. The fleshy parts of a mollusk can be further divided into the foot and the visceral mass. The foot is a distinctive molluscan feature, adapted in a variety of ways for locomotion. The visceral mass includes the organs for digestion, circulation, reproduction, and respiration.

In a brief survey of mollusks in the 1980s, many species were found in the park. Most are snails, both aquatic and terrestrial. One of the rarest is called the Guadalupe woodland snail, which was named Ashmunella carlsbadensis after being originally discovered nearby. The Guadalupe woodland snail is reportedly more tolerant of dry conditions and lower elevations than others in the Guadalupe Mountains. The park also has some species know as fingerclams, which are bivalves—related to clams, oysters and scallops. Instead of having spiral-like shells like snails, their shells consist of two symmetrical valves.

Bats

The most famous of the park's mammals are the bats. The park hosts 17 different bat species. The large colony of Brazilian (or Mexican) free-tail bats wows visitors every evening from spring through fall with its spectacular outflights. Two other species have also been found regularly in Carlsbad Cavern—cave myotis and fringed myotis bats. They typically roost in a different part of the cave and their exit flight is typically later in the evening than that of the free-tail bats.

But not all bat species roost in caves. Among the other species using the park are Eastern red bats and hoary bats, which roost in trees, and Western pipistrelle bats, which roost on rock cliffs and in cracks.

Bats are mammals, which means that they give live birth to their young (not lay eggs), are warm-blooded, have fur (not feathers), and are fed breastmilk (not insects) by their mothers. Bats are the only true flying mammals. All the bats in the area around Carlsbad Caverns National Park are insectivores (they eat insects).

The Brazilian free-tail bats weigh about ½ oz (13 g), which is equivalent to the weight of three nickel coins. Their wingspan is approximately 11 inches. Bat numbers in the Cavern are variable. The resident colony was around 400,000 in summer of 2005. During the spring and fall migration, the bat numbers in the cavern were documented as high as 793,000 in 2005. There are seasonal fluctuations of the numbers, as well as daily fluctuations. Researchers from Boston University have been assisting the park in getting accurate population estimates. They use advanced thermal infrared imaging cameras coupled with a custom-written visual recognition software program to count the bats.

At Carlsbad Cavern, the resident colony should not be called the maternity colony because it is typically greater than 50 percent male. The males and females roost mixed together in the same site. In many sites outside of the park, the really large Brazilian free-tail bat colonies are almost exclusively female and the males roost in smaller groups.

For lots more fascinating information on bats, check out the Bat Conservation International website at www.batcon.org.

Cave Swallows

Another migratory bird that nests in the park is the cave swallow. The cave swallow, a close relative of the cliff swallow, can be seen from early February to late October (sometimes even November) nesting just inside the entrance to Carlsbad Cavern, in the so-called twilight zone. The swallows provide entertainment for visitors by chattering, swooping, and making spectacular dives into and around the mouth of the cave.

The first cave swallows appeared in what is now Carlsbad Caverns National Park prior to 1930 and spread to Carlsbad Cavern in 1966. They make open cup-shaped nests out of mud that are used for several years with the birds frequently adding to the nest annually. Unlike the cliff swallow, a cave swallow's nest is not fully enclosed. It is shaped like a small half-cup; it is constructed of mud and plant fibers, and lined with feathers.

Cave swallows are insectivorous. They feed on a wide variety of insects and are considered to be opportunistic feeders. All prey is taken in flight with the birds only going to the ground to collect mud for nests.

A local researcher, Steve West, has been banding cave swallows at Carlsbad Cavern since 1980. In 2005, he recaptured a bird that had been banded in 1993 as a hatch-year individual, making it 12 years old! While most of the banding has been done to study the life history of the species, the original reason was to discover the winter range of the bird. One bird banded at Carlsbad Cavern was found dead in Jalisco, on the Pacific coast of Mexico, and provided the first clue of their winter range south of the United States.

The banding project continues and is one of the longest on-going banding studies in the United States. To date 5,000 volunteers from 38 states and 17 countries have helped to gather this information.

Reptiles

Among the 46 species of reptiles in the park are the gray-banded kingsnake, an endangered species in New Mexico, and two state-threatened species: the Rio Grande cooter (a turtle) and the mottled rock rattlesnake. Though rare in the state, the mottled rock rattlesnake is the most common snake seen in the park.

Rattlesnakes are far less common in the park than lizards. Most often seen are the several species of whiptail lizards, spiny lizards, and horned lizards. There are also two species of skinks and one gecko. Among the non-venomous snakes are such diverse animals as the Chihuahuan hook-nosed snake, Trans-Pecos ratsnake, and mountain patch-nosed snake.

The park also provides habitat for four species of turtles, one of which—the ornate box turtle—is not aquatic.

Other Invertebrates (corals, sponges, worms, etc.)

Horsehair worms are the aquatic adult phase of little-known invertebrate animals. The immature stages are parasites in the bodies of grasshoppers, crickets, cockroaches, and some beetles. When mature, they leave the host to lay eggs. These interesting creatures are not parasites of humans, livestock, or pets, and pose no public health threat. The adult "worms" mate in water and females lay long gelatinous strings of eggs. After the eggs hatch, scientists believe that each larva forms a protective covering or cyst. If the cyst is eaten by a suitable insect, the protective covering dissolves and the released larva bores through the gut wall and into the body cavity of the host. There, it digests and absorbs the surrounding tissue. When mature, it leaves the host insect to start the process again. Emergence from the host occurs only when the host is near water. Occasionally, they are found after a cricket or cockroach is killed by someone crushing the insect, at which time the worm begins to wiggle out of the insect's body.

Horsehair worms have also been seen in the caves of Carlsbad Caverns National Park and in streams in the Guadalupe Mountains. They are fascinating, but rarely encountered.

We can guess—fairly accurately—that the park provides habitat for numerous other strange invertebrate animals that are yet to be studied.

Crustaceans

Most of the known crustaceans in Carlsbad Caverns National Park are cave-dwelling creatures. These include intriguing animals such as copepods called Cyclops vernalis and branchiopods called water fleas (Holopedium amazonicum).

Also among the crustaceans are the group called isopods, including groups such as sowbugs, pillbugs and woodlice. The park has several species both below and above ground. Unfortunately, the above-ground pillbugs are probably not native.

Crayfish are the best-known crustaceans, and they have been found at Rattlesnake Springs. Identified as the red swamp or Louisiana crayfish, they also are not native to New Mexico.

Mammals

The park's 67 mammal species include some that are rarely seen, such as black bear and spotted skunk. Some of them are non-natives (eastern fox squirrel and Barbary sheep). Others are native animals that have been restored through reintroduction programs in the area, including javelina and pronghorn. Merriam's elk became extinct around the turn of the last century and the closely related Rocky Mountain elk was brought into the area to replace it. Desert bighorn sheep were extirpated from the park in the 1960s. Up to six other species may have been extirpated since European settlement.

Other native mammals in the park range from mule deer and cougar (mountain lion) to the small mammals such as ringtails; several species of ground squirrels, deer mice, and kangaroo rats; the desert shrew; and the Chihuahuan Desert pocket mouse, which was not documented in the park until the 21^st Century.

Of course, the most famous of the park's mammals are the bats, especially the large colony of Brazilian (or Mexican) free-tail bats that wows visitors every evening from spring through fall with its spectacular outflight. In all, the park hosts 17 different species of bats that use a variety of different habitats.

Insects, Spiders, Centipedes, Millipedes

The park has a rich fauna of invertebrate animals, most of which have not been formally surveyed. Nearly every time someone undertakes a study of the park's insects or other invertebrates, exciting revelations are made. For example, in 2003, Dr. John Abbott took his University of Texas class on a field trip to Rattlesnake Springs and documented a new species of damselfly for New Mexico, called Lenora's dancer. In 2005, the park sent some fireflies, also called "lightning bugs," to an expert for identification. It turned out that these insects, which are actually beetles, were a new genus for the state: Photuris.

In 2006, a long-term survey of the park's moths was undertaken by lepidopterist Eric Metzler. Results are very preliminary, but hundreds of species have already been collected, including some that may be entirely new species. Surveys of the park's butterflies have yielded more than 100 species, including the Carlsbad agave skipper and the Sandia hairstreak, the state butterfly of New Mexico. Thanks largely to the wooded riparian habitat with permanent water at Rattlesnake Springs, the park's list of damselflies and dragonflies is well over 60 species and includes such picturesque names as the saffron-winged meadowhawk (a dragonfly) and the desert firetail (a damselfly).

The park's underground environs harbor intriguing invertebrate wildlife as well. There are three species of cave (or camel) crickets known from Carlsbad Caverns National Park. These cricket-like insects have rounded backs and are nocturnal. Many cave crickets live in the front parts of caves only to leave at night to forage. Their diet consists of small insects, microbes, possibly algae or fungi, and each other. A number of other creatures, in turn, feed on cave crickets. These include bats, raccoons, and ringtails. Cave crickets and their eggs, and droppings are important food sources for other cave organisms.

The three known species from the park are Ceuthophilus carlsbadensis, C. longipes and C. conicaudus. As with many insects, these animals have not been given common names.

Ceuthophilus carlsbadensis is found in many caves throughout New Mexico and Texas and is very common in Carlsbad Cavern. It actually shows very little adaptation for living in caves and tends to live in food-rich areas, such as cave rooms with bat guano. On the other hand, Ceuthophilus longipes (known from numerous park caves) is more cave-adapted and is found in food-poor areas. C. longipes is smaller and lighter in color and has longer legs and antennae than C. carlsbadensis. The third species, Ceuthophilus conicaudus, falls between the other two species in cave adaptation traits. It is only found sparsely in Carlsbad Cavern, but is the dominant cave cricket in a few other park caves.

Other invertebrates found in the caves include isopods, troglophilic beetles, millipedes, centipedes, various spiders, and primitive creatures related to bristletails and silverfish.

Fish

Five species of fish have been found at Rattlesnake Springs. Two of these species are native—roundnose minnow and greenthroat darter. The other three species are non-native fish and they include green sunfish, largemouth bass, and western mosquitofish. In the summer of 2007, a project was completed to remove the non-native green sunfish and largemouth bass from the pond. These fish were relocated to an appropriate location on the Pecos River, where they are native. The western mosquitofish have only been found in the natural channel and these fish are removed when found.