Forest cobra
Forest cobra | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Squamata |
Suborder: | Serpentes |
Family: | Elapidae |
Genus: | Naja |
Subgenus: | Boulengerina
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Species: | N. melanoleuca
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Binomial name | |
Naja melanoleuca | |
Forest cobra distribution in green | |
Synonyms[2] | |
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The forest cobra (Naja melanoleuca), also commonly called the black cobra and the black and white-lipped cobra,[4] is a species of highly venomous snake in the family Elapidae. The species is native to Africa, mostly the central and western parts of the continent.[5] It is the largest true cobra species with a record length of 3.2 metres (10 feet 6 inches).[6][7]
Although it prefers
Taxonomy and evolution
The forest cobra is classified in the genus Naja of the family Elapidae. Naja melanoleuca was first described by American herpetologist Edward Hallowell in 1857.[11] The generic name Naja is a Latinisation of the Sanskrit word nāgá (नाग) meaning "cobra".[12] The specific epithet melanoleuca is Ancient Greek and means "of black and white". The word melano is Greek for "black",[13] while leuca comes from the Ancient Greek word for "white".[14] This species is also known as the black cobra and black and white-lipped cobra.[4]
The
The cladogram below illustrates the taxonomy and relationships among species of Naja:[16]
Naja |
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The population on São Tomé and Príncipe was recently described as a new species, Naja peroescobari,[17] and a recent study (based on a Multilocus genotype dataset and morphological analyses) suggests that N. melanoleuca is actually a group of five distinct species:[18]
- Republic of Congo, Angola.
- Naja subfulva Laurent, 1955 - forests and savanna woodlands in eastern, southern and central Africa: Chad, Nigeria, Cameroon, Central African Republic, Democratic Republic of Congo, Republic of Congo, Rwanda, Burundi, Uganda, Kenya, Tanzania, Somalia, South Sudan, Ethiopia, Mozambique, Malawi, Zambia, Zimbabwe, South Africa, Angola.
- Naja peroescobari Ceríaco et al. 2017 - São Tomé and Príncipe.
- Naja guineensis Broadley et al. in Wüster et al. 2018 - Upper Guinea forests, West Africa: Guinea-Bissau, Guinea, Liberia, Sierra Leone, Ivory Coast, Ghana, Togo.
- Gambia, Guinea, Ivory Coast, Ghana, Togo, Benin, Mali, Burkina Faso, Nigeria, Niger, Chad, Cameroon.
Description
The forest cobra is Africa's largest cobra of the genus Naja[8] and possibly the largest of all the true cobra (Naja) species in the world.[7][19] The length of an average adult is 1.4 to 2.2 m (4.6 to 7.2 ft), and they regularly attain lengths of 2.7 m (8.9 ft),[8][20] and lengths up to 3.2 m (10 ft) have been recorded in the wild.[21][6] The mean body mass of the species in one survey, which did not exclude juvenile cobras per se, was reported at a mean of 509.5 g (1.123 lb) while large, mature forest cobras are known to obtain weights of up to 2,000 to 3,600 g (4.4 to 7.9 lb).[20][22][23][24] Males and females grow to be similar in length, as there is no sexual dimorphism within this species.[25] The head of this snake is large, broad, flattened and is slightly distinct from the neck. It is a slightly depressed, tapered and moderately thick bodied snake with a slender tail that is medium in length. The body is compressed dorsoventrally (where the dorsal upper scales and the ventral lower scales meet at either side of the body) and sub-cylindrical posteriorly (the tail end of the body). The forest cobra has long cervical ribs capable of expansion to form a long, wedge shaped hood when threatened. The angle between the crown of the head and the side of the head between the eye, also known as the canthus, is distinct, while the snout is rounded. Its eyes are large with round pupils.[20] Females have larger heads than males, although the reason for this dimorphism is not clear. A study showed that females eat the same prey as males, so head size does not reflect a difference in diet.[26]
Scalation
Like other snake species, the forest cobra has skin covered in
The head, body and tail scalation of the forest cobra:[27]
- Dorsal rows at midbody: 19-21
- Ventrals: 201-214
- Subcaudals: 63-72 (paired)
- Anal plate: Single
- Upper labials: 7 (8)
- Upper labials touching eye: 3 & 4
- Preoculars: 1-2
- Postoculars: 2-3
- Lower labials: 8
- Temporals: variable
Venom
The venom of this cobra is a postsynaptic
The forest cobra is one of the least frequent causes of snake bite among the African cobras,[10] largely due its forest-dwelling habits but a bite by this species should be taken very seriously because it ranks as the 4th most venomous Naja (true cobra) species. The symptomology is thought to be very similar to that of the Egyptian cobra (Naja haje).[33] Clinical experience with this species has been very sparse, and few recorded bites have been documented. Deaths from respiratory failure due to severe neurotoxicity have been reported, but most victims will survive if prompt administration of antivenom is undertaken as soon as clinical signs of envenomation have been noted. Rare cases of spontaneous recoveries without the use of specific antivenom have also been seen; however, neglecting the use of antivenom places the patient at increased risk for major morbidity and mortality. If the snake becomes cornered or is agitated, it can quickly attack the aggressor, and because a large amount of venom is injected, a rapidly fatal outcome is possible. The mortality rate of an untreated bite is not exactly known but it is thought to be quite high. The forest cobra does not spit or spray its venom.[33]
Two cases from Liberia experienced severe neurological symptoms, including ptosis, nausea, vomiting, tachycardia, and respiratory distress. A child in Ghana died within 20 minutes after being bitten by a snake suspected to be from this species.[34]
Distribution and habitat
The forest cobra occurs mainly in
A snake of forest or woodland, it is the only one of Africa's cobras that will live in high forest.
Behavior
The forest cobra is an agile, diurnal species that climbs well and is one of the most aquatic of the true cobras of the genus Naja.[8] It is terrestrial, but it is a fast, graceful climber, known to ascend trees to a height of 10 m (33 ft) or more. It is quick moving and alert. It swims well and readily takes to the water; in some areas its main diet is fish and could be regarded as semi-aquatic. Although it is active mostly during the day (diurnal) in uninhabited areas, it can also be active by night (nocturnal) where it goes into urban areas. When not active, it takes cover in holes, brush piles, hollow logs, among root clusters or in rock crevices, or in abandoned termite mounds at forest fringe or clearings. In certain areas, it hides along river banks, in overhanging root systems or bird holes, and in urban areas will hide in junk piles or unused buildings. When agitated, it rears up to a considerable height and spreads a long, narrow hood. It can strike quickly, to quite a long distance, and if molested and cornered, it will rush forward and make a determined effort to bite. It is an alert and agile species of cobra.[33] Some authorities believe it is one of the most dangerous African snakes to be kept as many captive forest cobras are described to be particularly aggressive when handled.[8][9] This species is not able to "spit" its venom.[27]
Diet
Forest cobras will feed on a wide variety of prey,
Reproduction
This is an oviparous species.[8] In the summer, females will lay between 11 and 26 smooth white eggs, each roughly 3 to 6 cm (1.2 to 2.4 in). The eggs stick together in a bunch.[27] The eggs are laid in hollow trees, termite mounds, holes in the ground or females will make their own nests. Before mating, a pair of will "dance", raising their heads a foot or more off the ground and moving to and fro. This may continue for an hour before mating takes place, when the male presses his cloaca (the chamber into which the reproductive, urinary, and intestinal canals empty) against that of the female. Female forest cobras may stand guard and are irritable and aggressive during the breeding period. A female is liable to attack without provocation, with potentially fatal consequences for passersby if her nest is near a footpath.[7] Hatchlings are born completely independent and are usually 22 to 25 cm (8.7 to 9.8 in) in length,[20] although some sources claim that hatchlings may measure up to 47 cm (19 in)[27] Incubation period is anywhere from 55 to 70 days (or over 80 days in one captive study[37]) at temperatures of 27–30 °C (81–86 °F). These snakes are known to have a long lifespan. One captive specimen lived for 28 years, which was the record for the longest lived venomous snake in captivity,[36] but another specimen held at the Melbourne Zoo in Australia turned 35 on 1 September 2014.[26]
References
- ^ Jallow, M., Penner, J., Rödel, M.-O., Luiselli, L., Chippaux, J.-P., Gonwouo, N.L., Kusamba, C. & Zassi-Boulou, A.-G. 2021. Naja melanoleuca. The IUCN Red List of Threatened Species 2021: e.T13265900A13265907. https://dx.doi.org/10.2305/IUCN.UK.2021-1.RLTS.T13265900A13265907.en. Downloaded on 12 August 2021.
- ^ a b "Naja melanoleuca". Encyclopedia of Life. Retrieved 22 March 2014.
- ^ a b "Naja melanoleuca". Integrated Taxonomic Information System. Retrieved 11 January 2014.
- ^ a b c d e f "Naja melanoleuca". Clinical Toxinology Resource. University of Adelaide. Retrieved 22 March 2014.
- ^ ISBN 978-0-691-13295-2.
- ^ ISBN 978-1421427195.
- ^ ISBN 0-7614-7270-3.
- ^ ISBN 0-691-12436-1.
- ^ a b Haji, R. "Venomous snakes and snake bite" (PDF). Zoocheck Canada Inc. p. 14. Archived from the original (PDF) on 25 April 2012. Retrieved 27 February 2012.
- ^ a b c d "Immediate First Aid for bites by the Forest cobra (Naja melanoleuca)". Toxicology. University of California, San Diego. Archived from the original on 12 February 2014. Retrieved 22 March 2014.
Clinical experience with Naja melanoleuca has been very sparse, and few recorded bites have been documented.
- ^ Hallowell, Edward (1857). "Notice of a collection of Reptiles from the Gaboon country, West Africa, recently presented to the Academy of Natural Sciences of Philadelphia, by Dr. Henry A. Ford". Proceedings of the Academy of Natural Sciences of Philadelphia 9: 48–72. (Naja haje var. melanoleuca, new variation, pp. 61-62).
- ^ "Naja". The Free Dictionary. Princeton University. Retrieved 10 January 2014.
- ^ "melano". Merriam-Webster Medical Dictionary. Retrieved 10 March 2014.
- ^ "leuc-". Merriam-Webster Medical Dictionary. Retrieved 10 March 2014.
- ^ "Naja". Integrated Taxonomic Information System. Retrieved 11 January 2014.
- S2CID 14702999. Retrieved 11 January 2014.
- ISSN 1175-5334.
- PMID 30314221.
- ISBN 0-947464-30-1.
- ^ ISBN 978-0-88359-029-4.
- ^ Villiers, 1975
- ^ Luiselli, L., Angelici, F. M., & Akani, G. C. (2002). Comparative feeding strategies and dietary plasticity of the sympatric cobras Naja melanoleuca and Naja nigricollis in three diverging Afrotropical habitats. Canadian Journal of Zoology, 80(1), 55-63.
- ^ Marais, J. (2004). A Complete Guide to the Snakes of Southern Africa. South Africa: Struik Publishers.
- ^ Shine, R., Branch, W. R., Webb, J. K., Harlow, P. S., Shine, T., & Keogh, J. S. (2007). Ecology of cobras from southern Africa. Journal of Zoology, 272(2), 183-193.
- .
- ^ from the original on 27 October 2023. Retrieved 27 October 2023.
- ^ ISBN 1-86872-932-X.
- ISBN 1-56098-648-4.
- LCCN 73000229.
- ^ Fry, BG. "LD50 menu (Archived)". Archived from the original on 13 April 2012. Retrieved 22 March 2014.
- ^ Séan Thomas & Eugene Griessel – Dec 1999. "LD50 (Archived)". Archived from the original on 1 February 2012.
{{cite web}}
: CS1 maint: numeric names: authors list (link) - S2CID 9393261. Retrieved 6 November 2013.
- ^ ISBN 978-0-88359-029-4.
- ISBN 978-0-12-656470-9.
- ISBN 978-1-4729-6026-9.
- ^ ISBN 978-0-88359-029-4.
- JSTOR 1563487.
External links
- Immediate First Aid for bites by Forest cobra (Naja melanoleuca) Archived 12 February 2014 at the Wayback Machine
- Clinical Toxinology Resource
- Forest cobra (N. melanoleuca) Archived 24 September 2015 at the Wayback Machine
Media related to Naja melanoleuca at Wikimedia Commons