Black-headed and Flat-headed Snakes | Herps of Texas

Tantilla atriceps

Mon, 01 Jan 0001 00:00:00 +0000

Scientific name. Tantilla atriceps

Common Name. Mexican Black-headed Snake

General information. Not much is known about the natural history of Tantilla atriceps. It does feed upon centipedes and other insects, being immune to the venom produced by the centipedes. Tantilla atriceps is not considered a danger to humans.

Protected status. The Mexican Black-headed Snake is not a protected species in Texas and can be legally collected with a hunting license.

Diagnostic features. Smooth dorsal scales (15 rows at midbody) Divided anal plate Seven supralabials. First set of infralabials often contact each other under the chin

Coloration. Typical blackhead snake in that the only dark pigmentation found on its tan dorsal surface is a black cap on its head which extends as far as one or two scales back behind the parietals Posterior edge of the black cap is slighly convex or straight and does not extend down to the corner of the mouth. Some specimens may even have a light colored line separating the back of the cap from the rest of the body Ventral surface is red or pink.

General distribution. The U.S. range of Tantilla atriceps is restricted to two counties (Kleburg and Duval) in south Texas. In Mexico, it is found from central Coahuila south to San Luis Potosi, with isolated populations found in Tamaulipas.

Texas distribution. Tantilla atriceps is restricted to Kleburg and Duval Counties

Habitat. Tantilla atriceps prefers habitats which are moist, seeking refuge under boards and stones and is found in mountain canyons and desert washes, habitats which have a preponderance of moist refuges.

Reproduction. Tantilla atriceps is an egg layer, though nothing is known about its reproductive natural history.

Size. Tantilla atriceps is a thin snake, being no thicker than a pencil, with adult lengths ranging between 12.5-20 cm (5-8 in).

Map. Orange counties indicate new county records since previous Herps of Texas update in 1998; all other colored counties reflect known distribution prior to 1998 for species and/or subspecies. Map is based on museum voucher specimens.

Tantilla cucullata

Mon, 01 Jan 0001 00:00:00 +0000

Scientific name. Tantilla cucullata

Common Name. Trans-Pecos Black-headed Snake

General information. Being an infrequently seen snake in Texas, the natural history of Tantilla cucullata is not well known. Many of the handful of individuals collected were captured on summer nights following rainstorms. They are known to consume prey similar to that of the other Tantilla, accepting both centipedes and a variety of insects in captivity. It is a shy animal and considered not to be a threat to humans, though a large T. cucullata would be capable of biting a human.

Protected status. In Texas, T. cucullata is listed as threatened by the Texas Parks and Wildlife Department (listed as T. rubra diabola and T. rubra cucullata) and are afforded full protection from collection by the state.

Diagnostic features. There are no scalation differences between the two pattern types as both types have fifteen smooth dorsal scale rows at midbody and a divided anal plate.

Coloration. Tan dorsal surface All-white belly is in contrast with the other species of Tantilla found in Texas Black cap on top of head. There are two distinct patterns associated with the black cap in T. cucullata. In both pattern types, the posterior edge of the black cap of T. cucullata extends at least five dorsal scale rows behind the parietal scales, as well extends below the corner of the mouth. In fact, the infralabial scales are generally entirely black. One pattern type lacks any type of white coloration around the black cap Second pattern type consists of a white collar encircling the neck, separating the black cap of the head from the black coloration extending back from the nape of the neck. Also associated with this second pattern type are white spots found below and behind the eye, as well as occasional white spots found ont the snout.

General distribution. Tantilla cucullata has a restricted range, being only found in the U.S. in the state of Texas, specifically in the Big Bend and the eastern portion of the Trans-Pecos near Del Rio. Populations in adjacent areas of Mexico have yet to be described.

Texas distribution. NA

Habitat. Tantilla cucullata is found in the limestone hills of the Chihuahuan Desert, where the snake is presumed to seek refuge in the many cracks and crevices which affords it protection.

Reproduction. Little is known regarding the reproductive biology of these snakes, other than that they are egg layers, with a report of a clutch of three eggs being deposited in June. Nothing is known about the juveniles hatching time or size.

Size. Tantilla cucullata is one of the largest Tantilla found in the U.S., generally reaching lengths of 20-43 cm (8-17 in).

Tantilla gracilis

Mon, 01 Jan 0001 00:00:00 +0000

Scientific name. Tantilla gracilis

Common Name. Flat-headed Snake

General information. Tantilla gracilis feeds on arthropods, including centipedes, which also take advantage of the high moisture in such habitats. Tantilla gracilis is not a threat to humans who handle it, and captive snakes will often shove their heads into the folds of a captors hands looking for advantages to escape.

Protected status. The Flat-headed Snake is not a protected species in Texas and can be legally collected with a hunting license.

Diagnostic features. Smooth dorsal scales (in rows of 15 at midbody) Six supralabials Divided anal plate.

Coloration. Usually without a black cap on top of its head Tan or brown dorsal surface uninteruppted by dark pigment. Ventral surface is red or pink, which may actually be present on the supralabial and temporal scales on the head. Coloration of the head is generally darker than the rest of the body with certain individuals actually having a black cap present, though the cap does not contrast with the rest of the dorsum as strongly as seen in other species of Tantilla. The posterior edge of the black cap in T. gracilis is concave and does not extend below the corner of the mouth.

General distribution. The range of Tantilla gracilis extends from the lower Rio Grande valley northward to Kansas and Missouri.

Texas distribution. In Texas, Tantilla gracilis is found throughout the central and eastern portions of the state, including a few isolated populations in the Panhandle.

Habitat. A common inhabitant of many gardens and urban areas, Tantilla gracilis is also found in piles of rocks and leaves in a variety of habitats; the common theme of these habitats is a high moisture content.

Reproduction. Flat-headed Snakes are egg layers, laying clutches of one to four eggs in the late spring with young snakes hatching in the summer, measuring 7.5-9 cm (3-3.5 in) in length.

Size. Tantilla gracilis is a smallish snake, with adults growing to 18-20 cm (7-8 in).

Map. Map is based on museum voucher specimens. Last updated 24 October 2013.

Tantilla hobartsmithi

Mon, 01 Jan 0001 00:00:00 +0000

Scientific name. Tantilla hobartsmithi

Common Name. Smith’s Black-headed Snake

General information. Tantilla hobartsmithi consumes many different types of arthropod prey, preferring insect larvae, centipedes and millipedes. Not a danger to humans, T. hobartsmithi can be safely handled.

Protected status. The Smith’s Black-headed Snake is not a protected species in Texas and can be legally collected with a hunting license.

Diagnostic features. Smooth scales (in rows of 15 at midbody) Divided anal plate Seven supralabials First pair of infralabial scales do not touch each other on the underside of the chin.

Coloration. Brown or tan dorsal color Reddish or pink belly Underside of head and throat often grey in color. Black cap on top of its head that extends only as far back as the first, occasionally second, dorsal scale row behind the parietal scales on the head. A light colored line usually separates the posterior edge of the cap from the rest of the body. Posterior edge of the cap is also straight, or slightly convex, and does not extend below the corner of the mouth.

General distribution. Tantilla hobartsmithi is found in various portions of the southwestern U.S., with discontinous populations found in California, Nevada, Utah, Arizona, New Mexico and Texas. Additional isolated populations are also present in parts of northern Mexico.

Texas distribution. In Texas, Tantilla hobartsmithi is found in throughout most of the Trans-Pecos region as well as portions of the Edwards Plateau.

Habitat. The Smith’s Black-headed Snake is found in a variety of open habitats, ranging from the desert flatlands to forested mountain sides. It is usually associated with water and is often found when flipping boards, logs or stones, where the moisture is more likely to persist than elsewhere.

Reproduction. An egg layer, Tantilla hobartsmithi lays clutches of as many as three eggs during the month of June. Little is known about the juvenile snakes regarding their hatching dates or sizes.

Size. Adult Tantilla hobartsmithi typically measure 18-23 cm (7-9 in).

Tantilla nigriceps

Mon, 01 Jan 0001 00:00:00 +0000

Scientific name. Tantilla nigriceps

Common Name. Plains Black-headed Snake

General information. Tantilla nigriceps is an efficient predator of arthopods, specializing in the consumption of centipedes and spiders. It is also immune to the venom produced by centipedes, which is undoubtably injected into the snake during the centipede’s capture and subsequent ingestion by the snake. It is harmless to humans and can be handled safely by people.

Protected status. The Plains Black-headed Snake is not a protected species in Texas and can be legally collected with a hunting license.

Diagnostic features. Seven supralabials Smooth dorsal scales (15 rows at midbody) Divided anal plate.

Coloration. Tan (sometimes brown or grey) dorsal background Reddish midventral coloration Black cap on top of head that extends to a point two to five dorsal scale rows behind the head; this cap does not extend below the corner of the mouth.

General distribution. The range of Tantilla nigriceps includes much of Texas and portions of New Mexico, Oklahoma, Kansas, Colorado, Nebraska and Arizona. Portions of its range also extend into northern Mexico.

Texas distribution. The single subspecies of Tantilla nigriceps found in Texas, T. n. nigriceps, is present across the western two-thirds of the state.

Habitat. The Plains Black-headed Snake prefers microhabitats which can retain high levels of moisture, such as under stones, logs, and other piles of debris; it is found in a variety of macrohabitats, ranging from the grasslands to the deserts, but are only seen when the appropriate areas of higher moisture are present. Its nocturnal habits, however, make it infrequently seen in the open, with most sightings of the snake occurring under rocks and logs.

Reproduction. Tantilla nigriceps is an egg-layer, like other Tantilla species, with eggs laid in the the early part of the summer after breeding takes place during late April and May. The young hatch in the later portions of the summer.

Size. Tantilla nigriceps is small, reaching lengths of 18-35.5 cm (7-14 in) upon maturity, though in Texas, it is one of the largest members of the genus Tantilla.