Michael Price
Wed, December 22, 2021
The Trans-Pecos Black-headed Snake (Tantilla cucullata) is a harmless and secretive serpent that is one of five species of the genus Tantilla that call Texas home.
When it comes to rules, it seems that there is only one rule. And that is there are almost always exceptions to rules. But even that statement in and of itself is not a true rule, so maybe this isn’t the place to discuss philosophy.
My point about exceptions to the rules applies to the size of a species of rarely-seen serpent that, up until a decade or so ago, was known from less than 50 specimens.
The Trans-Pecos Black-headed Snake (Tantilla cucullata) is a harmless and uber-secretive serpent that is one of five species of the genus Tantilla that call Texas home. But unlike the other species of this genus which are quite diminutive (averaging less than 7 inches in total length), this variety of Black-headed snake is a true giant among its kinfolk. Most adults observed are well over 1 foot in total length, and many of those are larger, up to 16 inches in total length. The record-sized individual was just under 18 inches. In fact, it is more common to see the larger specimens than it is smaller individuals: out of the dozen or so of these creatures that I have been privy to find in the wild, only one was less than 12 inches.
Despite the markedly noticeable size differences, this species is like other family members in that it is rather unassuming in appearance. The body coloration varies slightly from tan to earthy-tone brown with no distinctive markings whatsoever. The head is entirely black, as if someone took the snake and dipped its head in a can of black paint. Occasionally, some individual populations will also have a white “ring” around the neck and a splash of white between the eye and the corner of the mouth. At one time, these two “morphs” were thought to be distinct enough from one another to allow for them to be taxonomically classified as two different subspecies of the same species, but genetic work has shown that these morphs are the same. The belly is an off-white coloration, and due to the dorsal scales being small and smooth, this snake oftentimes will have a glossy sheen appearance.
As their common name suggests, the Trans-Pecos Black-headed Snake has been observed throughout many of the high-elevation, heavily vegetated mountain ranges in western Texas. It is in these mountain ranges that it finds home in the grassland milieus where the soil consistency is conducive to the allowance of easy burrowing penetration. A secondary habitat is the fractured terrain in and among the mesas of the lower Stockton Plateau. Wherever it occurs, the soil must have a certain amount of moisture to hold the required high humidity that it prefers.
As with almost all other reptiles that reside in temperate climates, they undergo a period of inactivity during the coldest months of the year, allowing sexually mature adults to generate the sperm and eggs necessary for successful reproduction in the spring. Much akin to most other harmless snakes found in Texas, Trans-Pecos Black-headed Snakes are egg-laying animals. Mating occurs primarily during the month of May, and the 1-3 extremely elongate eggs are laid a month later in areas with sufficient humidity. After an approximate two-month incubation period the delicate babies hatch, and they are between a mere 5 inches in length, typically mimic the adults in color and pattern and are capable of fending for themselves from the moment they are born.
Trans-Pecos Black-headed Snakes are primarily fossorial, spending the clear majority of their life underground or beneath surface debris. It is in this habitat where they find their primary prey items of centipedes, spiders, scorpions, and insect larvae. When rainfall is abundant, this species will become surface active, and the vast majority of surface sightings are of individuals found crossing roadways in these conditions.
This species, while infrequently encountered (even by those who are actually looking for it!) is probably not as rare as once thought. However, it is listed as a Threatened Species with the Texas Parks & Wildlife Department and as such, it is protected from capture or harm.
This species is rear-fanged and has a mild toxin, but it lacks a sophisticated venom delivery system. The venom is rather weak as well, and is used for obtaining the fierce prey items rather than for defense. Therefore, like the majority of snakes that occur in this state, it is completely harmless to humans.
Michael Price is owner of Wild About Texas, an educational company that specializes in venomous animal safety training, environmental consultations and ecotourism. Contact him at wildabouttexas@gmail.com.
This article originally appeared on San Angelo Standard-Times: Trans-Pecos Black-headed Snake often an underground dweller in Texas
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