Green mamba characteristics, habitat, reproduction, nutrition

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Egbert Haynes
Green mamba characteristics, habitat, reproduction, nutrition

The green mamba Common is an African snake of the Elapidae family. Dendroaspis angusticeps (Smith, 1849) is also called the eastern green mamba due to its distribution in Africa, since there is another species of mamba with a similar coloration that occupies the western coast of the same continent..

This snake is very well adapted to living on trees, where it goes unnoticed thanks to its cryptic coloration with the foliage. It is a diurnal snake, thin and very agile..

Green Mamba (Dendroaspis angusticeps) By Dick Culbert from Gibsons, B.C., Canada [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)]

They usually establish their shelters in cavities in the trees or in the interception of branches where they roll up at night to spend the night. In contrast to other snakes of the genus Dendroaspis, Like the black mambas, they are relatively quiet snakes, preferring to flee if they feel threatened.

These snakes show little interest in cold-blooded prey like other reptiles and amphibians and prefer to feed on endothermic vertebrates. Although there have been cases of cannibalism in animals in captivity, this behavior has not been recorded in the wild..

Envenomations with snakes of the genus Dendroaspis represent a serious medical problem in sub-Saharan Africa. The knowledge of the components of the venom and the synergistic effects between them are of great interest for the elaboration of more effective antivenom serums..

Despite this, its venom, although not as toxic as that of the black mamba, is still life-threatening if the anti-venom is not administered..

Mambas are often mistaken for other snakes in the Colubridae family such as Philothamnus hoplogaster, another harmless arboreal snake from which it differs because its belly has a whitish or cream coloration. Because of this, many of the cases of green mambas accidents are due to inadequate precautions being taken..

Article index

  • 1 General characteristics
    • 1.1 Characteristics of the poison
    • 1.2 Composition
    • 1.3 Symptoms of poisoning
  • 2 Habitat and distribution
    • 2.1 Conservation
  • 3 Taxonomy
  • 4 Playback
    • 4.1 Oviposition
  • 5 Nutrition
  • 6 References

General characteristics

The coloration of these snakes is very striking. The adult specimens are dorsally emerald green to bright lime green, reminiscent of the color of the foliage of the trees it frequents and in which it camouflages very well. Ventrally they have a lighter and less conspicuous greenish color.

The young are usually easily distinguished by their yellowish-green coloration. These snakes are the ones that reach the smallest sizes within the genus Dendroaspis, both females and males tend to reach lengths slightly greater than two meters, with males being slightly larger than females.

They are slimmer and more stylized than the black mambas Dendroaspis polylepis. The lining of the mouth is bluish-white. The dentition of these snakes is of the proteroglyph type, which is why they have an advanced system of venom inoculation.

Venom characteristics

The green mambas possess a venom with neurotoxic characteristics. Although there is not a high number of ophidian accidents with these snakes, due to the toxicity of their venom they are included by the WHO in category 1 of toxicity and medical importance.

Severe poisoning can lead to death in as little as 30 min. These accidents are those in which several consecutive bites occur.

Composition

About 42 different proteins have been identified in its venom, in addition to the nucleoside adenosine. More than 60% of these proteins belong to the group of “three-fingered” toxins, very characteristic of the venoms of snakes of the Elapidae family. Some important neurotoxins are fasciculins and dentrotoxins.,

The venom of the green mamba does not present alpha-toxins like those present in the venom of the black mamba, which is why the latter are more dangerous. The high toxicity of the venom of the green mambas results from a synergy in the action of several of the components of the poison in the body, but not for a single specific component.

One of the most studied peptides is calcicludin, which has a high affinity for high-threshold voltage-activated Ca + channels, mainly those of the "L" type present in excitable cells that are involved in the release of neurotransmitters..

In addition to this, the venom of the green mambas presents around 10 toxins that interact with muscarinic receptors. It has a powerful effect on acetylcholine receptors. The venom also has procoagulant activities. About four polypeptides are related to K channel blockade+.

Symptoms of poisoning

The main symptoms after an ophidian accident with Dendroaspis angusticeps include localized inflammation in the bite area, loss of balance, profound nausea, lymphagitis, peripheral gangrene, progressive shortness of breath, irregular heartbeat, muscle spasms, and respiratory paralysis.

These symptoms can progressively worsen to be fatal if the specific serum is not administered quickly..

Habitat and distribution

Green mamba among the branches of a tree By David ~ O [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)]

This snake is restricted to the tropical rainforests of eastern Africa occupying part of Kenya, Tanzania, Mozambique, Malawi, eastern Zimbabwe, the Republic of South Africa (native) and the Democratic Republic of the Congo (Zaire). Its great abundance in these countries classifies it as a species of epidemiological importance

Although it is a typical species of lowlands and the east coast of Africa, there are records inland, such as in the Nyambeni forest in Kenya and the forests of eastern Zimbabwe.

Dendroaspis angusticeps it is a strictly arboreal species. It occupies a great diversity of coastal scrub, dunes, gallery forests and montane forests. Occasionally they can be observed on the ground in hunting or mobilization activities among isolated tree matrices..

Males move on the ground and fight on the ground during the breeding season. Near human establishments, they can be observed in wooded gardens and agricultural crops of tree species such as citrus, mangoes, coconut trees and avocados..

Conservation

Despite being a dangerous snake and that its habitats are continuously intervened, its conservation status in nature has not been evaluated. On the other hand, it is probable that in some distribution areas they suffer selective elimination and individuals are extracted from the wild to keep them as exotic pets..

Taxonomy

The gender Dendroaspis It is currently made up of four species which include Dendroaspis angusticeps, D. polylepis, D. jamesoni Y D. viridis.

The eastern green mambas are very similar in appearance to the black mambas, however, the coloration of both species is contrasting and there are obvious morphometric differences and in the cranial characteristics that widely differentiate them..

Originally the eastern greens and blacks were considered a single species with color variants.

Reproduction

Few reproductive data are known for this species in nature. It is known that the reproductive season of this species and the combats between males occur between April and June, just when a drop in temperature occurs and the length of the day decreases..

Males exhibit fighting behavior on the ground, which occurs when multiple individuals approach a receptive female. These matches generally occur between two males, but occasionally a third may participate. The duration of the matches for the right to mate can be extended by several hours.

After defining a winning male, he approaches the female. Courtship involves the male entwining himself with the female's body from head to tail tip, constantly wagging his tongue. When the female is ready to mate, she stops moving and copulation occurs..

If the female does not want to mate, she does not lift her tail for the male to insert one of his hemipenis, and it may also happen that it does not expand the cloaca. Intercourse can last from a few minutes to an hour.

Oviposition

These snakes are oviparous. In general, they stop feeding after the middle of their gestation period, which can last around 165 days until the months of October or November..

An adult female can lay up to 18 eggs in a clutch, each egg taking about 50 minutes to be laid. They are white and are approximately 65mm high by 35mm wide. Eggs are laid mainly in hollow logs or hidden in litter.

After laying, the snake coils motionlessly around the eggs. Several of the eggs in a clutch may be infertile or attacked by fungi. After about 65 days the hatchlings are ready to hatch, which takes up to 36 hours.

On the other hand, it is very common for snakes to die trying to emerge from the egg once they are ready to hatch. In addition to this, small green mambas with strange curvatures and other deformities have been reported at birth. The young are born measuring around 45 cm on average.

A female can reproduce again after three years, although this will depend on her ability to regain the body mass lost during pregnancy, due to the period of starvation..

Nutrition

Lateral view of Dendroaspis angusticeps By H. Krisp [CC BY 3.0 (https://creativecommons.org/licenses/by/3.0)]

The diet of the green mambas includes mainly endothermic animals. It feeds on several species of small birds found in the trees they frequent, as well as small rodents that make their dens on the trees or near their base..

Unlike the black mambas, the green mambas have a greater success in capturing adult birds and consume a greater abundance of chicks and eggs due to their preferentially arboreal habits..

Among the species of birds that consume are Quelea quelea, Andropatus importunus Phyllastrephus terrestris, Zosterops pallidus.

They have high rates of capture of small rodents mainly of the Muridae family and sometimes bats, in contrast to the black mambas, which consume a greater variety of mammals including juvenile representatives of the Leporidae, Viverridae and Lorisidae families, as well as small rodents of the families Sciuridae and Muridae.

Few are the reported cases of green mambas consuming other arboreal reptiles such as small lizards, although they are also included in their diet. All birds are captured in the foliage, however, the rodents that consume the green mambas are terrestrial, which indicates that they may go down to the ground to feed..

References

  1. Armitage, W. W. (1965). OBSERVATIONS ON DIFFERENCES IN MORPHOLOGY AND BEHAVIOR OF Dendroaspis angusticeps & D. polylepis. The Journal of the Herpetological Association of Africa, 1(1), 12-14.
  2. Barrett, J. C., & Harvey, A. L. (1979). Effects of the venom of the green mamba, Dendroaspis angusticeps on skeletal muscle and neuromuscular transmission. British journal of pharmacology, 67(2), 199.
  3. Branch, W. R., Haagner, G. V., & Shine, R. (1995). Is there an ontogenetic shift in mamba diet? Taxonomic confusion and dietary records for black and green mambas (Dendroaspis: Elapidae). Herpetological Natural History, 3, 171-178.
  4. Boycott, R. C; MORGAN, D.R. & PATTERSON, R. W (1989) observations on the captive propagation and maintenance of two Dendroaspis species, The Journal of the Herpetological Association of Africa, 36: 1, 76-76
  5. Haagner, G. V., & Carpenter, G. (1988). Notes on the reproduction of captive forest cobras, Naja melanoleuca (Snakes: Elapidae). The Journal of the Herpetological Association of Africa, 3. 4(1), 35-37.
  6. Haagner, G. V., & Morgan, D. R. (1989). The captive propagation of the eastern green mamba Dendroaspis angusticeps. International Zoo Yearbook, 28(1), 195-199.
  7. Harvey, A., & Karlsson, E. (1980). Dendrotoxin from the venom of the green mamba, Dendroaspis angusticeps. Naunyn-Schmiedeberg's archives of pharmacology, 312(1), 1-6.
  8. Jolkkonen, M., van Giersbergen, P. L., Hellman, U., Wernstedt, C., & Karlsson, E. (1994). A toxin from the green mamba Dendroaspis angusticeps: amino acid sequence and selectivity for muscarinic m4 receptors. FEBS letters, 352(1), 91-94.
  9. Lauridsen, L. P., Laustsen, A. H., Lomonte, B., & Gutiérrez, J. M. (2016). Toxicovenomics and antivenom profiling of the Eastern green mamba snake (Dendroaspis angusticeps). Journal of proteomics, 136, 248-261.
  10. Lloyd, C. N. (1974). Some observations on egg-laying behavior in the green mamba, Dendroaspis angusticeps. The Journal of the Herpetological Association of Africa, 12(1), 9-11.
  11. Müller, G. J., Modler, H., Wium, C. A., Veale, D. J. H., & Marks, C. J. (2012). Snake bite in southern Africa: diagnosis and management. Continuing Medical Education, 30(10).
  12. Osman, O. H., Ismail, M., & El-Asmar, M. F. (1973). Pharmacological studies of snake (Dendroaspis angusticeps) venom. Toxicon, eleven(2), 185-192.

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