Восточная зеленая мамба: Описание и особенности вида.

Species of venomous snake

The eastern green mamba (Dendroaspis angusticeps) is a highly venomous snake species of the mamba genus Dendroaspis native to the coastal regions of southern East Africa. Described by Scottish surgeon and zoologist Andrew Smith in 1849, it has a slender build with a bright green back and green yellow ventral scales. Adult females average around in length, and males are slightly smaller. In spite of common urban legends and misconceptions labeling the eastern green mamba an aggressive, fast moving “people chaser”, it is in fact a shy and elusive species that remains hidden in the trees, and is rarely seen. This seclusion is usually attributed to its arboreal habitat and green colouration, which acts as effective camouflage in its natural environment. Even with its deadly venom, the green mamba has to protect itself from predators, including birds of prey and other snakes, such as cobras. It has been observed engaging in ambush predation, a trait seen among many Viperidae species, contrary to the active hunting style typical of other Elapidae snakes. It preys on arboreal and winged animals, such as birds and their chicks and eggs, bats, and arboreal rodents such as mice, rats, and gerbils. Eastern green mamba venom consists of both neurotoxins and cardiotoxins. Symptoms of envenomation include swelling of the immediate bite wound area, dizziness, vertigo and nausea, accompanied by dehydration, labored breathing and difficult swallowing. This eventually will develop into arrythmia and convulsions—all progressing to respiratory paralysis, which results in a fatal lack of oxygen to the brain. Bites that are severe or not immediately treated on site can quickly prove deadly.

The eastern green mamba was first described as Naja angusticeps by Andrew Smith, a Scottish surgeon and zoologist, in 1849, who reported it from Natal and east to Maputo Bay. The specific name angusticeps is derived from the Latin word angustus, "narrow", and ceps, an abbreviated form of caput ("head") when used in a compound word. The German British zoologist Albert Günther described Dendroaspis intermedius from the Zambezi River in northern Mozambique in 1865. This was subsequently synonymised with D. angusticeps. a lumping diagnosis that remained in force until 1946, when the South African herpetologist Vivian FitzSimons published a paper after examining approximately 50 eastern green mamba and 85 black mamba specimens. He concluded that the differences in build, scalation, colouration and behaviour warranted splitting them into separate species. The British biologist Arthur Loveridge augmented FitzSimons' work with material from outside South Africa, noting some overlap in scalation but supporting the separation. A 2016 genetic analysis showed the eastern green and black mambas are each others' closest relatives, their common ancestor diverging from a lineage that gave rise to Jameson's mamba (Dendroaspis jamesoni) and the western green mamba (Dendroaspis viridis), as shown in the cladogram below.

The eastern green mamba is a large snake, with a slightly compressed and very slender body with a medium to long tapering tail. Adult males average around in total length, while females average This species rarely exceeds lengths of In general, the total length is 4–4.3 times the length of the tail. The adult eastern green mamba has bright green upperparts—occasionally with isolated yellow scales—and a pale yellow green belly. Sometimes they are duller coloured before moulting. Juveniles are blue green, becoming bright green when they are around long. The medium sized eyes have round pupils, The eastern green mamba has between 17 and 21 rows of dorsal scales at midbody, 201 to 232 ventral scales, 99 to 126 divided subcaudal scales, and a divided anal scale. Its mouth is lined with 7–9 supralabial scales above, the fourth one located under the eye, and 9–11 sublabial scales below. Its eyes have three preocular and 3–5 postocular scales.

The eastern green mamba is native to regions near the coastlines of Southern Africa and East Africa. Its range extends from Kenya south through Tanzania, Malawi, eastern Zimbabwe and parts of Zambia; it can also be found in Zanzibar and northern Mozambique. An elusive species, it is primarily arboreal (living in trees) and usually well camouflaged in foliage. Some herpetologists believe its habitat is limited to tropical rainforests in coastal lowlands. Unlike its close relative the black mamba, the eastern green mamba is rarely found in open terrain and prefers relatively dense, well shaded vegetation. As well as wild forest habitats, it is also commonly found in thickets and farm trees such as citrus, mango, coconut, and cashew. In coastal East Africa, it is known to enter houses and may even shelter in thatched roof dwellings. Specimens have been found at elevations up to above sea level. There is no evidence that the eastern green mamba migrates. Thought to be relatively sedentary, it can remain in the same location for days, apparently moving most commonly to find food or mates. On average, individuals move only about per day. They usually reach adult colouration at Another captive specimen lived 14 years. Sit and wait tactics may be successful with highly mobile prey, such as adult birds or rodents. Documented prey include the sombre greenbul, which occur in dense areas of natural and cultivated vegetation along Kenya's coastline. Ionides and Pitman (1965) reported a large bushveld gerbil in the stomach of a green mamba in Tanzania. Although the bushveld gerbil does not occur in Kenya, green mambas prey on the seven species of gerbil that inhabit parts of its range. Although the most commonly encountered green mamba, it generally avoids people. The peak period for bites is the species' breeding season from September to February, during which they are most irritable. A survey in southern Africa from 1957–1979 recorded 2,553 venomous snakebites, 17 of which were confirmed as eastern green mambas. Of these 17, 10 had symptoms of systemic envenomation, though no victims died. The snake tends to bite repeatedly, The median lethal dose (LD50) in mice is 1.3mg/kg The average dose able to kill a human is about 18–20 mg. Symptoms of envenomation by this species include pain and swelling of the bite site, which can progress to local necrosis or gangrene. Systemic effects include dizziness and nausea, difficulty breathing and swallowing, irregular heartbeat, and convulsions. which are anticholinesterase inhibitors that cause muscle fasciculation. Individually, most of these components do not exhibit potent toxicity in vitro,

Standard first aid treatment for any bite from a suspectedly venomous snake is the application of a pressure bandage, minimisation of the victim's movement, and rapid conveyance to a hospital or clinic. Due to the neurotoxic nature of green mamba venom, an arterial tourniquet may be beneficial. Tetanus toxoid is sometimes administered, though the main treatment is the administration of the appropriate antivenom. A polyvalent antivenom produced by the South African Institute for Medical Research is used to treat eastern green mamba bites.