A Texas coral snake (Micrurus tener tener) showing its characteristic red-yellow-black banding pattern. While generally shy and nonconfrontational, the snake's neurotoxic venom can produce extreme pain, and even death.
Credit: National Natural Toxins Research Center at Texas A&M University-Kingsville
Coral snakes are small, vibrantly colored, highly venomous snakes. They have the second-strongest venom of any snake (the black mamba has the most deadly venom), but they are generally considered less dangerous than rattlesnakes because coral snakes have a less effective poison-delivery system.
Coral snakes are separated into two groups: the Old World coral snakes [found in Asia] and the New World coral snakes [found in the Americas], according to Sara Viernum, a herpetologist based in Madison, Wisconsin. "New World coral snakes are considered some of the most toxic snakes in North America because their venom contains powerful neurotoxins," she said.
Coral snakes are slender and small, typically between 18 and 20 inches long (45 to 50 centimeters), with some species reaching 3 feet (1 meter). According to DesertUSA, the Western coral snake can be as skinny as a pencil. They have bulbous, almost-neckless heads, rounded noses and similar-looking tails, meaning that it can be hard to tell a snake’s head from its tail.
They use this characteristic to fool attackers by burying their heads in their coiled bodies and raising their tails — which look quite similar to their heads. “The idea for this behavior is that it’s always better to lose your tail than your head,” Viernum said.
When provoked, coral snakes will sometimes make a popping sound by expelling air from their cloaca, a single opening for the urinary, reproductive and intestinal tract, to startle the threat. According to researcher Joseph F. Gemano Jr. in an article in Reptiles magazine, these "microfarts" have been observed in other species, such as the Western hook-nosed snake. Scientists disagree about the behavior's purpose. Some have speculated that it is a mating call, but Gemano said that in his research, the fart was always associated with an aggressive-defensive behavior.
The most distinctive physical characteristics of coral snakes are their brightly colored and patterned bodies, short, fixed fangs and potent venom, according to Viernum. While only some species have elements of coral coloring, all species have eye-catching patterns and colors: red bands flanked by yellow bands.
Because of the coral snake's dangerous reputation, many nonpoisonous snakes disguise themselves as coral snakes by having similar body patterns. For example, Viernum said, the nonvenomous shovel-nosed snakehas yellow bands that touch black bands. Also, “Scarlet kingsnakes look very similar to Eastern coral snakes, but the red bands of a scarlet kingsnake are next to the black bands whereas the red bands of an eastern coral snake are next to the yellow bands.”
Viernum said a rhyme was penned “as a way for people to quickly and easily differentiate between a nonvenomous snake and the toxic coral snake.” One version of the rhyme goes:
Red and yellow, can kill a fellow;
Red and black, friend of Jack.
Viernum said that the rhyme is “fairly accurate for snakes in the U.S. but it fails with the Old World coral snakes and many New World species found in Central and South America.” In other parts of the world, coral snakes may have red bands touching black bands, have pink and blue banding, or have no banding at all.
The best way to identify a coral snake is by its head, which is blunt and black to behind the eyes, and its bands that completely circle the body instead of breaking at the belly.
Coral snakes are in the Elapidae family, as are cobras, sea snakes and black mambas. There are about 70 species of New World coral snakes and about 15 species of Old World coral snakes.
The taxonomy of coral snakes, according to the Integrated Taxonomic Information System (ITIS), is:
- Kingdom: Animalia
- Subkingdom: Bilateria
- Infrakingdom: Deuterostomia
- Phylum: Chordata
- Subphylum: Vertebrata
- Infraphylum: Gnathostomata
- Superclass: Tetrapoda
- Class: Reptilia
- Order: Squamata
- Suborder: Serpentes
- Infraorder: Alethinophidia
- Family: Elapidae
- Genera (Old World): Calliophis, Hemibungarus and Sinomicrusus
- Genera (New World): Leptomicrurus, Micruroides and Micrusus
Species: The following are descriptions of the most typical or impressive coral snakes:
Eastern coral snake (Micrurus fulvius): Ranging from North Carolina to Florida and Texas, this is the brightest of North American coral snakes. According to the Florida Museum of Natural History, its body is entirely covered in bright bands of black, red and yellow. Narrow bright yellow rings separate wider red and black rings. There is a yellow ring behind the snake’s black snout. The tail is ringed in black and yellow, with no red.
Western or Arizona Coral snake (Micruroides euryxanthus): This Southwestern North American snake has the same basic color pattern as its Eastern counterpart, though the colors are slightly muted. The yellow bands, especially, are paler, and can be actually be white, according to the Arizona-Sonora Desert Museum. They are also wider than the Eastern coral snake’s yellow bands.
Blue Malayan coral snake (Calliophis bivirgatus): This stunning snake lives in the jungles of Southeast Asia. Unlike its North American cousins, it does not have bands. Instead, it has a deep blue body with light blue or white stripes on each side, and a gorgeous, coral-red head and tail, according to Ecology Asia.
Coral snakes that live in forested or jungle areas spend most of their time burrowed underground or in leaf piles, according to the University of Michigan Museum of Zoology’s Animal Diversity Web(ADW). They like marshy and wooded areas, but also live in the scrubby sandhills of the Southeast United States.
Western coral snakes live primarily in the Sonoran Desert of Arizona and Northern Mexico. According to Arizona Leisure, they like to live under rocks or burrow into sand or soil, and are often found in the rocky areas around Saguaro cacti.
Coral snakes are nocturnal and reclusive. Because of their secretive habits, they may be found in suburban areas. They spend most of their time keeping cozy in burrows or under rocks or rotting leaves. According to the Savannah River Ecology Laboratory, they are most commonly seen in the spring and fall. These snakes are shy and will often flee from predators.
Coral snakes eat lizards and other small, smoothed-scaled snakes. National Geographic reported that Eastern coral snakes will eat frogs, and Western coral snakes are particularly fond of devouring blind or black-headed snakes, according to the Arizona-Sonora Desert Museum.
Unlike many other venomous snakes that give birth to live young, coral snakes lay eggs. According to the ADW, they are the only venomous snakes in North America to do so. Eastern coral snakes lay six or seven eggs in the summer that hatch in early fall. Western coral snakes lay two to three eggs. Babies are born brightly colored, fully venomous, and 7 inches (17 cm) long.
According to the New Mexico Department of Game and Fish, unlike most other venomous snakes, the coral snake cannot contract its fangs into its mouth. Instead, they are constantly out and erect. Their fangs are relatively weak.
According to National Geographic, though their venom is highly toxic, no deaths from coral snake bites have been reported in North America since the late 1960s, when antivenin was developed. No deaths from a Western coral snake have been reported at all. Nevertheless, their bites can be extremely painful and, if left untreated, can lead to cardiac arrest.
Coral snakes’ small, fixed fangs and small mouth mean that it is difficult for them to puncture human skin — let alone leather boots. Humans are mostly bitten when trying to pick up a coral snake. Because of their small size, these snakes don’t carry much venom in their fangs, so they may try to hold onto their victim for some time.
According to Viernum, “One of the most distinctive behavioral characteristics of coral snakes is how they deliver their venom. Since their fangs are short and fixed, they deliver their venom through chewing motions.” She described this process as “similar to the way Gila monsters deliver their venom to prey.”
The snake’s neurotoxic venom causes rapid paralysis and respiratory failure in its prey; however, according to the National Institutes of Health, it can take many hours for symptoms to appear in humans. Additionally, there is often little or no pain or swelling in humans from a coral snake bite. If untreated by antivenom, however, symptoms will take effect. They include slurred speech, double vision, and muscular paralysis.
- Sara Viernum and her team at "The Wandering Herpetologist," are dedicated to providing news, facts, and educational information about amphibians and reptiles.
- Savannah River Ecology Laboratory: What Do We Know About Coral Snakes?
- Reptiles magazine: Coral Snake Research