Real cobras
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Glasses snake ( well well ) |
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| Laurenti , 1768 |
The real cobras ( Naja ) are poisonous snakes ( Elapidae), which occur in about 30 species in large parts of Africa and Asia. The most striking feature of a cobra is the expandable neck shield, in some species ( spectacled snake Naja naja , monocle cobra Naja kaouthia ) with eyeglass markings , which is spread in a threatening position.
features
Real cobras reach an average length of 1.50 meters, some species can be up to 2.30 meters long. They are characterized above all by the fact that they are able to expand their neck skin into a hood with the help of elongated neck ribs and particularly loose and flexible skin in the neck area, which in some species is also provided with a conspicuous mark. In addition to the species of real cobras, representatives of other genera are also able to do this, such as the significantly larger king cobra ( Ophiophagus hannah ) or the South African spitting cobra ( Hemachatus haemachatus ). Further characteristics of the real cobras are the round pupils and the smooth, sloping back scales of the animals.
Way of life
All species of the real cobras live on the ground and often hide in rodents, hollow trees or other suitable hiding places. They are diurnal and can be found in almost all habitats, sometimes also in rice fields or even in settlements and cities, where they become active between twilight and night.
nutrition
Cobras feed on small mammals, birds, other snakes, lizards, and amphibians. A bite usually kills the prey.
defense
Most cobras try to flee when threatened. If this is not possible, for example because they have been disturbed in their hiding place, cobras (including the king cobra ) assume a typical threatening pose, in which they raise their upper bodies wide and spread their necks. They fixate the potential attacker and sometimes sway their heads back and forth for minutes while they utter hissing threatening sounds. From this position, a sudden strike can occur. 15 Well species are also so-called spitting cobras , which can spit their venom very precisely at an opponent from a distance of about two to three meters. They usually aim at the head; If the poison gets into the eyes, damage and even blindness can occur.
species
According to DNA analyzes, 29 recent species are currently divided into four sub-genera :
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Well Laurenti, 1768:
- Naja atra Cantor, 1842 (Chinese cobra, also Taiwanese or Vietnamese cobra)
- Naja kaouthia Lesson, 1831 (Monocle Cobra)
- Well mandalayensis Slowinski & Wüster, 2000
- Well well (Linnaeus, 1758) (spectacled snake)
- Well oxiana (Eichwald, 1831)
- Well philippinensis Taylor, 1922
- Well sagittifera Wall, 1913
- Well samarensis Peters, 1861
- Well siamensis Laurenti, 1768
- Well sputatrix Boie, 1827
- Well sumatrana Müller, 1890
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Uraeus Wagler, 1830:
- Naja anchietae Bocage, 1879
- Well annulifera Peters, 1854
- Well arabica Scortecci, 1932
- Well senegalensis Trape, Chirio & Wüster in Trape et al. , 2009
- Naja haje (Linnaeus, 1758) (uraeus snake)
- Naja nivea (Linnaeus, 1758) (Cape cobra)
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Boulengerina Dollo, 1886:
- Naja (Boulengerina) annulata Buchholz & Peters in Peters, 1876
- Naja christyi (Boulenger, 1904)
- Naja melanoleuca Hallowell, 1857 (black and white hat snake, also black and white cobra)
- Well multifasciata (Werner, 1902)
- Well peroescobari Ceríaco, Marques, Schmitz & Bauer, 2017
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Afronaja Wallach et al. 2009 (African spitting cobras):
- Naja ashei Wüster & Broadley, 2007 (East African Spitting Cobra)
- Well katiensis Angel, 1922
- Well mossambica Peters, 1854
- Well nigricincta Bogert, 1940
- Well nigricollis Reinhardt, 1843
- Naja nubiae Wüster & Broadley, 2003 (Nubian spitting cobra)
- Naja pallida Boulenger, 1896 (Red Spitting Cobra)
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Incertae sedis :
- † Well antiqua Rage, 1976
- † Well iberica Szyndlar, 1985
- † Well robusta Meylan, 1987
The best known cobra species is the up to 2 meter long spectacled snake ( well well ). Animals from India and Sri Lanka can be recognized by the eyeglass markings on the neck. They live in humid areas, especially in South Asia.
African spitting cobras (subgenus Afronaja ) are black to pink in color, and some animals have a black band around their necks. Spitting cobras occur everywhere and do not avoid humans too much. For example, it can happen that animals get into cities and into people's homes. They are nocturnal and hunt lizards, birds, frogs and other snakes.
Another well-known species is the uraeus snake ( Naja haje ) from North Africa and the Middle East, which can go into a state of rigidity when threatened. The Egyptian queen Cleopatra is said to have poisoned herself with her poison . In 2003 a new species was described with the Nubian spitting cobra ( Naja nubiae ). It is colored brown-gray and has two dark bands around the neck. The snake, first thought to be a red spitting cobra ( Naja pallida ), was identified as a new species of cobra by genetic analysis. It was not until 2007 that the largest representative of the spitting cobras, the East African Naja ashei , was described.
The strongest poison of African cobra species is attributed to the black and white cobra ( Naja melanoleuca ) and the cape cobra ( Naja nivea ). The poison of the cape cobra kills small animals in just a few seconds; humans can die within an hour without immediate aid. It can be up to 1.6 meters long and has large eyes with a round pupil. The color of the animal varies from brown-yellow to black. Their habitats are dry, stony areas and sandy rivers.
The distribution area of the Chinese cobra ( Naja atra ) is southern China, northern Laos, Taiwan, and northern Vietnam, which is why it is also known locally as Taiwanese or Vietnamese cobra.
Cobra poison
The neurotoxic toxins of the cobras are extremely potent and act by antagonism at the nicotine receptors of the neuromuscular endplate on the peripheral nervous system , which can lead to paralysis with respiratory paralysis . The victim can be paralyzed or killed by the bite.
Some species are able to accurately inject their venom into the eyes of an attacker over a short distance, which causes severe burning pain and swelling and can lead to blindness . This type of defense is particularly true of the African spitting cobras, which are able to inject their venom up to four meters. The poison of these species has a high proportion of tissue-destroying substances, which is atypical for poisonous snakes. Bites attributed to the puff adders found in the same area were in part caused by these cobras.
The cobra poison is important for medical research because the enzyme lecithinase, which inhibits blood clotting , can be used effectively against viruses . There are now many effective serums available , which have reduced deaths from snake bites.
An international research team has examined the genome of the spectacled snake ( well well ) with regard to the toxins encoded there. It contains 139 genes that code substances from 33 families of toxins, 19 of which are considered to be primarily responsible for the toxicity. These are responsible for the symptoms of a bite such as nausea, visual disturbances, muscle paralysis and systemic effects such as bleeding or disorders of the cardiovascular system. The focus of the research is on nine three-finger toxins (3FTx) named after their tripartite form, which, like other snake toxins , are expected to have therapeutic applications.
mythology
In Indian mythology, the cobra is widespread: it is an attribute of the Hindu -Gottes Shiva and other deities from his environment ( Bhairava , Kali , Chamunda and Others..). The head of the meditating Jaina - Tirthankaras Parshvanata is also protected by a snake hood ( naga ).
See also
Individual evidence
- ↑ Edward R. Chu, Scott A. Weinstein, Julian White & David A. Warrell (2010): Venom ophthalmia caused by venoms of spitting elapid and other snakes: Report of ten cases with review of epidemiology, clinical features, pathophysiology and management . Toxicon 56, pp. 259-272.
- ↑ W. Wüster et al. (2007): The phylogeny of cobras inferred from mitochondrial DNA sequences: Evolution of venom spitting and the phylogeography of the African spitting cobras (Serpentes: Elapidae: Naja nigricollis complex) . Molecular Phylogenetics and Evolution 45, pp. 437–453 ( full text ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this note .; PDF; 321 kB )
- ^ V. Wallach, W. Wüster & D, G. Broadley (2009): In praise of subgenera: taxonomic status of cobras of the genus Naja Laurenti (Serpentes: Elapidae) . Zootaxa 2236, pp. 26–36 ( PDF )
- ↑ a b Chinese cobra, Naja atra , in: Go: ruma
- ↑ Luis MP Ceríaco, Mariana P. Marques, Andreas Schmitz and Aaron M. Bauer. 2017. The “Cobra-preta” of São Tomé Island, Gulf of Guinea, is A New Species of Naja Laurenti, 1768 (Squamata: Elapidae) . Zootaxa . 4324 (1); 121-141. DOI: 10.11646 / zootaxa.4324.1.7
- ↑ uniprot.org: Long neurotoxin 2
- ↑ uniprot.org: Cobrotoxin
- ^ Paul Morawitz : Anticoagulant effect of cobra poison. In: German Archive for Clinical Medicine 80, 1904, pp. 340–355
- ↑ Kushal Suryamohan, Sajesh P. Krishnankutty, Joseph Guillory, Matthew Jevit, Markus S. Schröder: The Indian cobra reference genome and transcriptome enables comprehensive identification of venom toxins . In: Nature Genetics . January 6, 2020, ISSN 1546-1718 , p. 1–12 , doi : 10.1038 / s41588-019-0559-8 ( nature.com [accessed January 14, 2020]).
