Texas blind snakes are not blind. Although their eyesight is greatly reduced, they are able to distinguish changes in light intensity. They communicate both interspecifically, as well as intraspecifically, through the use of attractant and deterrent pheromones. The primary food source for these snakes are ant and termite larvae, which they often find by foraging in colonies of these social insects. Texas blind snakes are known for foraging amidst colonies of army ants (Neiv amyrmex nigrescens). Normally, these ants attack threats, but Texas blind snakes are able to produce cloacal secretions, consisting of glycoproteins with free fatty acids, that act as a deterrent toward the ants and allow them to go unharmed in colonies. Additionally, these snakes are attracted to the pheromones that army ant workers secrete. They are also able to use cloacal secretions as an interspecific signal to deter ophiophagus snakes. Finally, the secretions serve as intraspecific signals as well, in that other blind snakes of both sexes are attracted to them.
Communication Channels: chemical
Other Communication Modes: pheromones
Perception Channels: chemical
Texas blind snakes are sometimes killed on highways or drown in suburban swimming pools. Domestic cats also prey on these snakes. The most severe threats to this species are habitat alteration and the use of pesticides. Texas blind snakes are listed as Threatened and are protected in the state of Kansas.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
There are no known adverse effects of Texas blind snakes.
There are no known positive impacts of Texas blind snakes on humans.
As mentioned in the predation section, a commensal relationship has been proposed between Texas blind snakes and eastern screech owls. In this relationship, the owls experience reduced larval parasite populations in their nests, potentially increasing chick size, and the snakes are not harmed assuming they are able to return to the ground in a reasonable amount of time.
Commensal/Parasitic Species:
Termites and ants make up 54 to 64% of the diet of Texas blind snakes. Other soft-bodied larval and nypmhal arthropods are also consumed opportunistically. They have been shown to eat the eggs of these insects as well. One hypothesis regarding their choice of soft-bodied prey over adult arthropods is that the chitonous bodies of adult ants and the heads of termites could potentially be harmful to the blind snake digestive system, although this has not been confirmed.
Through the use of olfaction, these blind snakes are able to detect pheromones in the trails of species such as army ants. Often these snakes will move in a concertina or lateral undulatory motion until they encounter those trails, at which time they perform a combination of touching the external nares to the trail, pausing for up to a minute, and flicking the tongue rapidly.
The common form of consuming prey in many snakes, such as king snakes, involves jaw ratcheting mechanisms in which each side of the loosely ligamented upper jaw moves independently (unilaterally) from the other and the pterygoid teeth “walk” over the prey, driving it down the digestive tract. The family Leptotyphlopidae, which includes Texas blind snakes, however, possess a much different mechanism of prey-consumption modes. Rather than employ the maxilla in driving prey down the digestive tract, they incorporate the lower jaw in a process called mandibular raking. In this mechanism, they uses bilaterally synchronous motions of the toothed lower jaw to consume soft-bodied insect prey. Often when they are searching for prey, they begin to sway their head horizontally until the snout contacts a larva or a pupa, upon which the blind snake will position its mouth over the prey, sometimes pinning it to the substrate. The larvae is swallowed up until right behind the head, which is broken off by rubbing it against the substrate.
Animal Foods: insects; terrestrial non-insect arthropods
Primary Diet: carnivore (Insectivore , Eats non-insect arthropods)
Leptotyphlops dulcis has an extensive range, from the Nearctic region to the Neotropics. In North America, this species extends from the southwest United States to northern Mexico. In the United States, L. dulcis is found in southwestern Kansas, western Oklahoma, central Texas, southern New Mexico, and southeastern Arizona. In Mexico, this species ranges from Chihuahua, Coahuila, and Tamaulipas, to Nuevo Leon, San Luis Potosi, Veracruz, Queretaro, Hidalgo, and Puebla.
Biogeographic Regions: nearctic (Native )
Texas blind snakes can be found in arid grasslands and desert fringes as long as moisture and surface cover, such as rocks and logs, are available. They can be found from sea level to roughly 2100 m. Plant species that are prevalent in preferred habitat include yucca, cacti, and thornbush. It is common to find these snakes in prairie grasslands and oak-juniper woodlands, as well as on canyon bottoms and rocky hillsides. Texas blind snakes have been known to take advantage of water sources and compost piles common in suburban settings.
Texas blind snakes are fossorial. They live in a variety of habitat types, as long there is ample food and loose, moist soil. These snakes have been found in arboreal habitats as well in several cases involving following their ant prey, as well as occasionally being deposited in nests by screech owls. Texas blind snakes sometimes follow earthworm trails, a behavior which is assumed to be linked to its lack of specialized digging modifications prevalent in other fossorial reptiles, as this snake does not eat earthworms. If given a choice, clay-loam soils are preferred over other types.
Range elevation: 0 to 2100 m.
Habitat Regions: temperate ; tropical
Terrestrial Biomes: desert or dune ; savanna or grassland ; scrub forest
No data on lifespan are available.
Texas blind snakes are small snakes. Length ranges from 10 to 30 cm. They are 4 to 5 mm in diameter, have small, uniform, smooth scales, blunt heads, and reduced eyes. Color varies from reddish brown to pink or gray with most pigment in the seven most dorsal scale rows. There are 14 anterior and midbody rows, 12 rows anterior to the vent, and 10 rows around the tail, with a total of 199 to 255 middorsal scales. They have an undivided anal plate. Leptotyphlops dulcis can be distinguished from Leptotyphlops humilis because it has supraocular scales between the eyes, thus creating a total of three scales between the oculars (one prefrontal and the two supraocular). Leptotyphlops dulcis has no teeth on the maxilla, only on the anterior half of the lower jaw.
There is no apparent sexual dimorphism in Texas blind snakes and dissection of the tail is necessary to determine gender. There are four subspecies, two are found north of Mexico: L. dulcis dulcis and L. dulcis dissectus.
Range length: 10 to 30 cm.
Other Physical Features: heterothermic
Sexual Dimorphism: sexes alike
Eastern screech owls are known predators of Texas blind snakes. In fact, they are involved in an unusual, potentially commensalist relationship, in which live Texas blind snakes have been observed in the nests of screech owls. In a study conducted by Gelbach and Baldridge (1987), these owls brought live blind snakes to their nests. The snakes remained in the nest for days, living in the lower levels of the nest off of soft-bodied nest parasite larvae, until the owlets fledged and the snake was able to escape to the ground. It has been proposed that Texas blind snakes are able to survive the initial capture by the owl as it possesses a unique writhing mechanism that allows it to coil around the beak of the owl and remain relatively unharmed upon arriving back at the nest.
Additionally, although raiding army ant colonies do not appear to prey on Texas blind snakes, they are a danger to blind snakes if they detect it amongst their ranks. The pheromones in Texas blind snake cloacal secretions protect them from attack. These pheromones also appear to repel ophiophagous snakes as well. Predators range from large centipedes, snakes, and birds, to mammals such as moles, armadillos, skunks, and domestic cats.
Known Predators:
Anti-predator Adaptations: cryptic
Males follow female pheromone trails to find mates. "Mating balls" of blindsnakes are not uncommon, where several males try to copulate with the same female at once. Mating occurs under a rock or in a crevice and the male wraps himself around the female in a corkscrew shape.
Mating System: polygynandrous (promiscuous)
Because Texas blind snakes live largely underground, little information is available regarding their reproductive behavior. The mating period occurs from late March to June in Texas. While age at reproduction is not known for females, size has been noted. Females averaging 19.3 to 22.5 cm long have been found gravid. Interestingly, females only possess a right oviduct with well-developed seminal receptacle and a short vaginal pouch. While not much is known regarding the ovarian cycle of these snakes, but females have been found containing developed eggs in early summer, which suggests spring ovulation and late summer oviposition.
Males possess a single, smooth hemipenis that is not distally forked and the sulcus spermaticus is deeply grooved. Additionally, males have spindle-shaped testes at the front caudal third of the body. The left testis usually has fewer lobes than the right testis, usually four to six lobes. While the testicular cycle has not been determined, it is probably similar to that of Leptotyphlops humilis.
Breeding interval: Studies performed on their close relative, Leptotyphlops humilis, have suggested that females do not produce eggs annually.
Breeding season: The closely related species, Leptotyphlops humilis, mate in spring to early summer.
Range number of offspring: 1 to 6.
Average number of offspring: 4.
Key Reproductive Features: iteroparous ; seasonal breeding ; sexual ; fertilization ; oviparous
Texas blind snakes nest in cracks in the earth, roughly 0.76 meters below the surface in colonies. In these colonies, snakes sit atop the clutches of eggs, including multiple clutches in layers. Eggs are long and narrow (15mm by 4.5mm) and have parchment-like shells. Hatching occurs in the fall, late August to September, with roughly 7 cm pink hatchlings emerging.
Parental Investment: female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Female)
Rena dulcis, also known commonly as the Texas blind snake, the Texas slender blind snake, or the Texas threadsnake,[4] is a species of snake in the family Leptotyphlopidae. The species is endemic to the Southwestern United States and adjacent northern Mexico. Three subspecies are currently recognized, including the nominate subspecies described here.[4][3]
The Texas blind snake appears much like a shiny earthworm. It is pinkish-brown (puce) in color with a deep sheen to its scales. It appears not to be segmented. The eyes are no more than two dark dots under the head scales. Unique among snakes, their upper jaws contain no teeth, and the lower jaw is incredibly short (less than half the length of the skull). When ingesting prey, the snakes flex the front of their short lower jaw quickly in a raking motion to fling prey into their esophagus.[5]
Adults can grow to approximately 27 cm (11 in) in total length, including the tail.[6]
On the top of the head, between the ocular scales, L. dulcis has three scales (L. humilis has one scale).[6]
The Texas blind snake spends the vast majority of its time buried in loose soil, only emerging to feed or when it rains and its habitat floods with water. It is often found after spring rains and mistaken for an earthworm. If handled it usually squirms around and tries to poke the tip of its tail into the handler. This is a completely harmless maneuver and likely serves as a distractive measure. The mouth is far too small to effectively bite a human being.
Commensal behavior has been observed with the eastern screech owl in which the owl carries live Texas blind snakes back to the nest, where the snakes help to clean the nest of parasites.[7]
The diet of R. dulcis consists primarily of termite and ant larvae.
Common names for R. dulcis include the following: burrowing snake,[8] eastern worm snake,[8] plains blind snake, Texas blind snake, Texas Rena,[8] Texas slender blind snake, Texas threadsnake,[4] Texas worm snake,[8] worm snake.[8]
Rena dulcis is found in the southwestern United States and northern Mexico. In the USA it occurs in southwestern Kansas, western Oklahoma including the panhandle, central and southern Texas, west through southern New Mexico to southeastern Arizona. In northern Mexico it has been reported in Chihuahua, Coahuila, Tamaulipas, Nuevo León, San Luis Potosí, Veracruz, Querétaro, Hidalgo, and Puebla.
The type locality given by Baird and Girard is "Between San Pedro and Camanche [sic] Springs, Tex." (Comanche Springs, Texas).[2]
Gauging wild blind snake populations is virtually impossible due to their secretive nature. However, like many other native Texas species, R. dulcis is known to be detrimentally affected by the red imported fire ant.
The following three subspecies are recognized as being valid.[3]
Nota bene: A trinomial authority in parentheses indicates that the subspecies was originally described in a genus other than Rena.
Rena dulcis, also known commonly as the Texas blind snake, the Texas slender blind snake, or the Texas threadsnake, is a species of snake in the family Leptotyphlopidae. The species is endemic to the Southwestern United States and adjacent northern Mexico. Three subspecies are currently recognized, including the nominate subspecies described here.
