Coral snake

Coral Snake
Coral snake (Micrurus sp.)
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Elapidae
Genus: Leptomicrurus
Calliophis
Micrurus
Micruroides
Species

See text.
The Distribution of the US Coral Snakes, some species range father south

The coral snakes are a large group of elapid snakes that can be subdivided into two distinct groups, Old World coral snakes and New World coral snakes. There are 11 species of Old World coral snake in one genus (Calliophis), and over 65 recognized species of New World coral snakes in three genera (Leptomicrurus, Micruroides, and Micrurus).

Contents

North American Coloration Patterns

Coral snakes are most notable for their red, yellow/white, and black colored banding. (Several nonvenomous species have similar coloration, however, including the Scarlet Kingsnake, the Milk Snake, and the Chionactis occipitalis annulata.) In some regions, the order of the bands distinguishes between the non-venomous mimics and the venomous coral snakes, inspiring some folk rhymes — "Red on yellow, kill a fellow; red on black, friend of Jack" (for similar looking Milk Snakes). However, this only reliably applies to coral snakes native to North America: Micrurus fulvius (Eastern or common), Micrurus tener (Texas), and Micruroides euryxanthus (Arizona), found in the southern and western United States. Coral snakes found in other parts of the world can have distinctly different patterns, have red bands touching black bands, have only pink and blue banding, or have no banding at all.

Most species of coral snake are small in size. North American species average around 3 feet (91 cm) in length, but specimens of up to 5 feet (150 cm) or slightly larger have been reported. Aquatic species have flattened tails, to act as a fin, aiding in swimming.

Behavior

Coral snake showing typically reclusive behavior of hiding under rotting wood. This one was over 30 inches long, but less than an inch across.

Coral snakes vary widely in their behavior, but most are very elusive, fossorial snakes which spend the vast majority of their time buried beneath the ground or in the leaf litter of a rainforest floor, only coming to the surface during rains or during breeding season. Some species, like Micrurus surinamensis are almost entirely aquatic and spend most of their lives in slow-moving bodies of water that have dense vegetation.

Like all elapid snakes, coral snakes use a pair of small fangs fixed in the front of their top jaw to deliver their venom. They feed on smaller snakes, lizards, frogs, and nestling birds and rodents etc. The venom takes time to fully take effect.[1]

Coral snakes have a tendency to hold on to a victim when biting, unlike vipers which have retractable fangs and tend to prefer to strike and let go immediately. Coral snakes are not aggressive or prone to biting however, and account for less than one percent of the number of snake bites each year in the United States. Most coral snake bites in the United States are legitimate occurring because of accidental contact with the snake while engaged in an outdoor activity such as gardening.

Distribution

Eastern Coral Snake, Micrurus fulvius

New World coral snakes exist in the southern range of many temperate U.S. states.

Coral Snakes are found in scattered localities in the southern Coastal Plain from North Carolina to Louisiana, including all of Florida. They can be found in pine and scrub oak sandhills habitats in parts of this range but sometimes inhabit hardwood areas and pine flatwoods that undergo seasonal flooding.[2]

There is controversy about the classification of the very similar Texas coral snake as a separate species. Its habitat, in Texas, Louisiana, and Arkansas, is separated from the eastern habitat by the Mississippi River. The map here shows the denser population in the southeast United States but coral snakes have been spotted as far north as Kentucky.[3]

The Arizona coral snake, clearly a separate species, is found in central and southern Arizona, extreme southwestern New Mexico and southward to Sinaloa in western Mexico. It occupies arid and semiarid regions in many different habitat types including thornscrub, desert-scrub, woodland, grassland and farmland. It is found in the plains and lower mountain slopes from sea level to 5800 feet (1768 m); often found in rocky areas. [4]

Danger to humans

New World coral snakes possess the most potent venom of any North American snake, followed closely behind by the Mojave rattlesnake. A coral snake must only administer 3-5mg of venom to be fatal to the average adult human; the Mojave rattlesnake must inject 10-15mg to be lethal. Most venomous snakes must inject between 75-100mg of venom to be fatal [5]. However, relatively few bites are recorded due to their reclusive nature and the fact they generally inhabit sparsely populated areas. According to the National Institutes of Health, there are an average of only 15-25 coral snake bites nation-wide each year [6].

When confronted by humans, coral snakes will almost always attempt to flee, and bite only as a last resort. In addition, coral snakes have short fangs (proteroglyph dentition) that cannot penetrate thick leather clothing. Any skin penetration, however, is a medical emergency that requires immediate attention. Coral snakes have a powerful neurotoxin that paralyzes the breathing muscles; mechanical or artificial respiration, along with large doses of antivenin, are often required to save a victim's life. There is usually only mild pain associated with a bite, but respiratory failure can occur within hours.

The bite of a coral snake may soon become increasingly more dangerous, ironically because of the relatively few bites each year. Production of coral snake antivenin in the United States has ceased because it is not profitable. According to Pfizer, the owner of the company that used to make Coralmyn, it would take over $5-$10 million to put toward researching a new synthetic antivenin. The cost was just too large for the small number of cases presented each year. The current antivenin stock is scheduled to expire in 2010, after two consecutive expiration date extensions approved by the FDA. Foreign pharmaceutical manufacturers have produced other coral snake antivenins, but the costs associated with licensing them in the United States have stalled availability (see above).[7]

Taxonomy

Old World

Genus Calliophis

New World

Genus Leptomicrurus

  • Leptomicrurus collaris collaris (Schlegel, 1837)
  • Leptomicrurus collaris breviventris (Roze & Bernal-Carlo, 1987)
  • Leptomicrurus narduccii narduccii (Jan, 1863)
  • Leptomicrurus narduccii melanotus (Peters, 1881)

Genus Micruroides

  • Micruroides euryxanthus australis (Zweifel & Norris, 1955)
  • Micruroides euryxanthus euryxanthus (Kennicott, 1860)
  • Micruroides euryxanthus neglectus (Roze, 1967)

Genus Micrurus

  • Micrurus alleni alleni (Schmidt, 1936)
  • Micrurus alleni richardi (Taylor, 1951)
  • Micrurus alleni yatesi (Taylor, 1954)
  • Micrurus ancoralis jani (Schmidt, 1936)
  • Micrurus ancoralis ancoralis (Jan, 1872)
  • Micrurus annellatus annellatus (Peters, 1871)
  • Micrurus annellatus balzanii (Boulenger, 1898)
  • Micrurus annellatus bolivianus (Roze, 1967)
  • Micrurus browni browni (Schmidt & Smith, 1943)
  • Micrurus browni importunus (Roze, 1967)
  • Micrurus browni Taylori (Schmidt & Smith, 1943)
  • Micrurus diastema diastema (Duméril, Bibron, & Duméril, 1854)
  • Micrurus diastema aglaeope (Cope, 1859)
  • Micrurus diastema alienus (Werner, 1903)
  • Micrurus diastema affinis (Jan, 1858)
  • Micrurus diastema apiatus (Jan, 1858)
  • Micrurus diastema macdougalli (Roze, 1967)
  • Micrurus diastema sapperi (Werner, 1903)
  • Micrurus dissoleucus dissoleucus (Cope, 1860)
  • Micrurus dissoleucus dunni (Barbour, 1923)
  • Micrurus dissoleucus melanogenys (Cope, 1860)
  • Micrurus dissoleucus meridensis (Roze, 1989)
  • Micrurus dissoleucus nigrirostris (Schmidt, 1955)
  • Micrurus distans distans (Kennicott, 1860)
  • Micrurus distans michoacanensis (Duges, 1891)
  • Micrurus distans oliveri (Roze, 1967)
  • Micrurus distans zweifeli (Roze, 1967)
  • Micrurus dumerili antioquiensis (Schmidt, 1936)
  • Micrurus dumerili carinicaudus (Schmidt, 1936)
  • Micrurus carinicauda (Schmidt, 1936)
  • Micrurus dumerili colombianus (Griffin, 1916)
  • Micrurus dumerili transandinus (Schmidt, 1936)
  • Micrurus dumerili venezuelensis (Roze, 1989)
  • Micrurus elegans elegans (Jan, 1858)
  • Micrurus elegans veraepacis (Schmidt, 1933)
  • Micrurus ephippifer zapotecus (Roze, 1989)
  • Micrurus ephippifer ephippifer (Cope, 1886)
  • Micrurus filiformis filiformis (Günther, 1859)
  • Micrurus filiformis subtilis (Roze, 1967)
  • Micrurus frontalis frontalis (Duméril, Bibron, & Duméril, 1854)
  • Micrurus frontalis brasiliensis (Roze, 1967)
  • Micrurus frontalis mesopotamicus (Barrio & Miranda 1967)
  • Micrurus hemprichii hemprichii (Jan, 1858)
  • Micrurus hemprichii ortoni (Schmidt, 1953)
  • Micrurus hemprichii rondonianus (Roze & Da Silva, 1990)
  • Micrurus langsdorffi langsdorffi (Wagler, 1824)
  • Micrurus langsdorffi ornatissimus (Jan, 1858)
  • Micrurus laticollaris laticollaris (Peters, 1870)
  • Micrurus laticollaris maculirostris (Roze, 1967)
  • Micrurus lemniscatus lemniscatus (Linnaeus, 1758)
  • Micrurus lemniscatus carvalhoi (Roze, 1967)
  • Micrurus lemniscatus diutius (Burger, 1955)
  • Micrurus lemniscatus frontifasciatus (Werner, 1927)
  • Micrurus lemniscatus helleri (Schmidt & Schmidt, 1925)
  • Micrurus limbatus limbatus (Fraser, 1964)
  • Micrurus limbatus spilosomus (Perez-Higaredo & Smith, 1990)
  • Micrurus mipartitus mipartitus (Duméril, Bibron, & Duméril, 1854)
  • Micrurus mipartitus anomalus (Boulenger, 1896)
  • Micrurus mipartitus decussatus (Duméril, Bibron, & Duméril, 1854)
  • Micrurus mipartitus semipartitus (Jan, 1858)
  • Micrurus multifasciatus multifasciatus (Jan, 1858)
  • Micrurus multifasciatus hertwigi (Werner, 1897)
  • Micrurus nigrocinctus babaspul (Roze, 1967)
  • Micrurus nigrocinctus coibensis (Schmidt, 1936)
  • Micrurus nigrocinctus divaricatus (Hallowell, 1855)
  • Micrurus nigrocinctus mosquitensis (Schmidt, 1933)
  • Micrurus nigrocinctus nigrocinctus (Girard, 1854)
  • Micrurus nigrocinctus ovandoensis (Schmidt & Smith, 1943)
  • Micrurus nigrocinctus wagneri (Mertens, 1941)
  • Micrurus nigrocinctus yatesi (Dunn, 1942)
  • Micrurus nigrocinctus zunilensis (Schmidt, 1932)
  • Micrurus psyches circinalis (Duméril, Bibron & Duméril, 1854)
  • Micrurus psyches donosoi (Hoge, Cordeiro, & Romano, 1976)
  • Micrurus psyches psyches (Daudin, 1803)
  • Micrurus spixii spixii (Wagler, 1824)
  • Micrurus spixiii martiusi (Schmidt, 1953)
  • Micrurus spixii obscurus (Jan, 1872)
  • Micrurus spixii princeps (Boulenger, 1905)
  • Micrurus steindachneri steindachneri (Werner, 1901)
  • Micrurus steindachneri orcesi (Roze, 1967)
  • Micrurus surinamensis surinamensis (Cuvier, 1817)
  • Micrurus surinamensis nattereri (Schmidt, 1952)
  • Micrurus tener fitzingeri (Jan, 1858)
  • Micrurus tener maculatus (Roze, 1967)
  • Micrurus tener microgalbineus (Brown, & Smith, 1942)
  • Micrurus tener tener (Baird, & Girard, 1853)
  • Micrurus tschudii olssoni (Schmidt & Schmidt, 1925)
  • Micrurus tschudii tschudii (Jan, 1858)

Mimicry

New World coral snakes are known to mimic False coral snakes, snake species whose venom is less toxic. This is a rare example of Mertensian mimicry. There are also non-venomous species whose pattern appears to mimic that of the coral snake. The evolutionary origin of these similarities is still a matter of some controversy[8]. Species that appear similar to coral snakes include:

Notes

  1. ↑ "Coral Snakes, coral snake, pictures". http://www.pestproducts.com/coral_snakes.htm. Retrieved 24 November 2009. 
  2. ↑ University of Georgia, Savannah River Ecology, Snakes of Georgia and South Carolina
  3. ↑ Western Connecticut State University
  4. ↑ Arizona-Sonora Desert Museum
  5. ↑ [1]
  6. ↑ [2]
  7. ↑ [3]
  8. ↑ Brodie III, Edmund D., Moore, Allen J. (1995). "Experimental studies of coral snake mimicry: do snakes mimic millipedes?". Animal Behavior 49: 534-6. 

Further reading

External links

Coral Snake Website

http://www.fda.gov/cber/safety/wyecor102808.htm