Anchieta's cobra: Difference between revisions
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==Behaviour and ecology== | ==Behaviour and ecology== | ||
===Behaviour=== | ===Behaviour=== | ||
This is a terrestrial and nocturnal species, foraging for food from dusk onwards, often venturing into poultry runs. During the day it is often seen basking near its preferred retreat, usually an abandoned termite mound, | This is a terrestrial and nocturnal species, foraging for food from dusk onwards, often venturing into poultry runs. During the day it is often seen basking near its preferred retreat, usually an abandoned termite mound, a hole in a rock, hollow tree or under dense vegetation. Although primarily ground dwelling it can also be found in small shrubs. The Anchieta's cobra is more aggressive than closely related species such as the [[Snouted cobra]], but otherwise similar in habits. Although this species will posture in a hostile way when provoked, it will flee when given the opportunity. It has been known to feign death, but it is not as inclined to display this behaviour as is the [[Rinkhals]] (''Hemachatus haemachatus''). This is not a spitting cobra.<ref name=Marais/><ref name=Broadley>Broadley, D.G. (1983). FitzSimons' Snakes of Southern Africa. Delta Books, Johannesburg. ISBN 0947464301</ref> | ||
===Diet=== | ===Diet=== | ||
Revision as of 17:26, 14 June 2012
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 Anchieta's cobra
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The Anchieta's cobra (Naja anchietae), also called the Angolan cobra is a species of cobra in the Elapidae family; it is native to the southern regions of Africa.
Etymology
The Anchieta's cobra was first described by Portuguese zoologist José Vicente Barbosa du Bocage in 1879.[2] The generic name Naja is a Latinisation of the Sanskrit word nāgá (नाग) meaning "cobra". The specific epithet anchietae refers to José de Anchieta, a Portugese explorer of Africa.[1]
Description
The Anchieta's cobra is a medium to large, slightly depressed, tapered and moderately slender bodied snake with a medium length tail. The body of the snake is compressed dorsoventrally and subcylindrical posteriorly. This cobra species can easily be identified by its relatively large and quite impressive hood, which it expands when threatened. The head of this species is broad, flattened and slightly distinct from the neck. The canthus is distinct. The snout is rounded. The eyes are medium in size with round pupils. Dorsal scales are smooth, shiny, without pits and oblique.[3] Adults average around 1.0 m (3.28 ft)[4] but it is not uncommon to find specimens between 1.2 m (3.94 ft) and 1.8 m (5.91 ft) in length.[5] Maximum size attained by this species is just a bit over 2.0 m (6.56 ft), but these are rare cases. The longest recorded male was 2.31 m (7.58 ft) long and was caught in Windhoek, Namibia. The longest recorded female was slightly shorter at 2.18 m (7.15 ft) and was found 25 km (15.53 mi) south of Shakawe, Botswana.[1]
Juveniles are yellow above and below, dorsally with dark scale margins forming irregular transverse lines and a broad black band encircling the neck. Adults gradually darken to light or dark brown, the dark band on the neck fades out. The venter is usually yellow, heavily blotched with dark brown, and the throat band, covering ventrals 12-23, becomes purple-brown. A banded phase sometimes occurs in the southern part of the species' range, black with six to eight yellow bands on the body and one to three on the tail. The light bands are usually as wide or wider than the dark ones. This banded phase has been noted in 13% of males and 22% of females.[1]
Scalation
Midbody scales are in 17 rows with 179-200 ventrals. There are 51-56 paired subcaudals and the anal shield is entire. There are 7 (sometimes 8) upper labials that do not enter the eye and 8 or 9 (rarely 10) lower labials, as well as 1 preocular and 2 postoculars. Temporals are variable, 1+2 or 1+3.[4]
Distribution and habitat
Geographical distribution
This species is mainly limited to southeastern Africa and it can be found in southern Angola, northern Namibia, northern Botswana, western Zambia and parts of northwestern Zimbabwe. Previous reports also included Mozambique, Malawi, Swaziland and southern Democratic Republic of the Congo.[6]
Habitat
The Anchieta's cobras preferred habitat is mesic savanna grasslands, semi desserts, rocky areas but is also often found nearby or in humans settlements, where they sometimes seek shelter under houses. It is especially found in wooded areas along rivers and wetlands.[4] This cobra is never found in forest or desert regions. This species is usually found at low altitudes, but it has been observed at elevations of 2000 m (6561.68 ft) above sea level.[7]
Behaviour and ecology
Behaviour
This is a terrestrial and nocturnal species, foraging for food from dusk onwards, often venturing into poultry runs. During the day it is often seen basking near its preferred retreat, usually an abandoned termite mound, a hole in a rock, hollow tree or under dense vegetation. Although primarily ground dwelling it can also be found in small shrubs. The Anchieta's cobra is more aggressive than closely related species such as the Snouted cobra, but otherwise similar in habits. Although this species will posture in a hostile way when provoked, it will flee when given the opportunity. It has been known to feign death, but it is not as inclined to display this behaviour as is the Rinkhals (Hemachatus haemachatus). This is not a spitting cobra.[4][5]
Diet
This cobra is a feeding generalist, preying on amphibians such as toads and frogs, other reptiles including lizards and other snakes, birds (including poultry), birds eggs, and mammals such as rats and mice.[4][5]
Predators
The Anchieta's cobra is preyed upon by birds of prey (particularly secretary birds and snake eagles), mammalian carnivores (e.g. mongooses) and other snakes.[5]
Reproduction
Like other cobras it is oviparous, laying between 47 and 60 eggs in early summer. Hatchlings average between 22 cm (8.66 in) and 34 cm (13.39 in) in length and are completely independent at birth.[4]
Venom
Venom of this species is primarily neurotoxic and cardiotoxic. As a relatively large species, it can inject relatively large quantities of venom in a single bite. It has been known to have caused human fatalities.[7]
Cited references
- ↑ 1.0 1.1 1.2 1.3 Naja anchietae BOCAGE, 1879 at The Reptile Database. Accessed 13 June 2012.
- ↑ Bocage,J.V.B. du 1879. Reptiles et batraciens nouveaux d'Angola. J. Acad. Sci. Lisbon 7: 97-99
- ↑ Anchieta's cobra: General details at Clinical Toxinology. Accessed 13 June 2012.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Marais, Johan (2004). A Complete Guide to the Snakes of Southern Africa. Cape Town, South Africa: Struik Nature. pp. 104–105. ISBN 1-86872-932-X.
- ↑ 5.0 5.1 5.2 5.3 Broadley, D.G. (1983). FitzSimons' Snakes of Southern Africa. Delta Books, Johannesburg. ISBN 0947464301
- ↑ BROADLEY, D.G. & W. WÜSTER 2004. A review of the southern African ‘non-spitting’ cobras (Serpentes: Elapidae: Naja). African Journal of Herpetology 53 (2):101-122
- ↑ 7.0 7.1 Naja anchietae at Armed Forces Pest Management Board. United States Department of Defense. Accessed 13 June 2012.