Micrurus tener
Micrurus tener, commonly known as the Texas coral snake, is a species of venomous snake in the family Elapidae. The species is endemic to the southern United States and northeastern and central Mexico. Five subspecies are recognized as being valid, including the nominotypical subspecies, Micrurus tener tener, which is found in both the US and Mexico, and is also commonly known as the Texas coral snake. The species Micrurus tener was once considered to be a subspecies of the eastern coral snake (Micrurus fulvius ).
The Texas coral snake is a colorful venomous snake native to the United States and Mexico. It has the traditional coloration associated with coral snakes: black, yellow, and red rings. It has smooth dorsal scales, a rounded head, and the eyes have round pupils. Males of this species are typically smaller than females.
Texas coral snakes range from the southern United States south to northeastern and central Mexico. They are found in the states of Texas, Louisiana, Arkansas, Tamaulipas, San Luis Potosí, Guanajuato, Querétaro, and Morelos. Texas coral snakes inhabit mixed forests, woodlands, grassland, savanna, shrubland, and desert. They also often occur in vegetation along rivers, streams, and creeks, in gardens, and undeveloped parklands in cities.
Texas coral snakes are shy, secretive animals. They are solitary and typically nocturnal. These snakes are fossorial and spend most of their time underground or hiding in leaf litter, under logs. They can be seen crawling on the surface, after heavy rains, when the nighttime temperatures rise above 78 °F (26 °C). When grabbed suddenly, or sometimes just when touched, they may thrash about, swing around, and bite. Sometimes they are calm, and then suddenly swing around and bite, for no apparent reason.
Texas coral snake venom is a powerful neurotoxin, causing neuromuscular dysfunction. Until 2006, no deaths from coral snake bites had been reported since the 1970s in the United States; however, rare, fatal bites have occurred, according to several scientific journals in the 1980s and 1990s.
Because of the low profits, the production of coral snake antivenin has been discontinued for several years. Prior to the availability of antivenin, the fatality rate of coral snake envenomations has been estimated at 10%, and death was primarily due to respiratory or cardiovascular failure as a result of paralysis induced by the neurotoxic venom.
Wyeth Pharmaceuticals, a wholly owned subsidiary of Pfizer, produced antivenin for the eastern coral snake, which can also be used for treatment of envenomation by the Texas coral snake. However, the last lot produced (Lot L67530) has an expiration date of January 31, 2020. As of July 2021, Pfizer indicates that antivenom is available and one source states that production has resumed.
A coral snake (genus Micrurus ) is proteroglyphous, meaning it has a pair of deeply grooved, semihollow, chisel-shaped, fixed fangs in the front of its upper jaw, through which the venom is injected and encouraged via a chewing motion. Coral snakes do not necessarily need to bite and hold on for a brief time to deliver a significant amount of venom. They expel venom quickly during extraction into collection media in the lab. Severe envenomations have occurred after a quick bite. Many bites from coral snakes do not inject any venom at all (known as a dry bite). A bite from any coral snake should be considered an extremely serious medical emergency, and medical treatment should be sought immediately, because symptoms of envenomation are known to sometimes delay manifestation for as long as 24 hours, but once present, often progress very rapidly.
Texas coral snakes are carnivores. They prey on other snakes, primarily earth snakes, and other small fossorial species. They also occasionally eat small lizards, and rarely rodents.
Texas coral snakes are oviparous and females typically lay a clutch of 3-12 eggs in June. The eggs are laid underground or in loose soil or under leaf-litter and hatch in September.
There are no major threats to Texas coral snakes at present. In some areas of their range, they suffer from habitat loss due to urbanization. Because these snakes are venomous people also kill them because of fear.
According to the IUCN Red List, the adult population size is unknown but presumably exceeds 100,000 individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.
