Элапиды: Ядовитые змеи мира

Family of venomous snakes
Automatic taxobox
| image =
| image caption = From the top left clockwise: king cobra, oriental coral snake, inland taipan and black mamba
| taxon = Elapidae
| authority = F. Boie, 1827
| subdivision ranks = Subfamilies and genera
| subdivision ref = efn|The elapids in the past were considered to have two subfamilies–the Elapinae made of terrestrial species and Hydrophiinae made of the marine species. In 1997, Slowinski, Knight and Rooney found in their phylogenetic analysis using amino acid sequences from venom proteins, that the Australasian terrestrial species nested within Hydrophiinae. This led to removing the Australasian terrestrial species and placing them in the Hydrophiinae. These studies have found coral snakes, cobras and mambas, kraits, and African gartersnakes forming successive outgroups to Hydrophiinae. is a family of snakes characterized by their permanently erect fangs at the front of the mouth. Most elapids are venomous, with the exception of the genus Emydocephalus. Many members of this family exhibit a threat display of rearing upwards while spreading out a neck flap. Elapids are endemic to tropical and subtropical regions around the world, with terrestrial forms in Asia, Australia, Africa, and the Americas and marine forms in the Pacific and Indian Oceans. Members of the family have a wide range of sizes, from the white lipped snake to the king cobra. Most species have neurotoxic venom that is channeled by their hollow fangs, and some may contain other toxic components in various proportions. The family includes 55 genera with around 360 species and over 170 subspecies.

Terrestrial elapids look similar to the Colubridae; almost all have long, slender bodies with smooth scales, a head covered with large shields (and not always distinct from the neck), and eyes with rounded pupils. Also like colubrids, their behavior is usually quite active and fast, with most of the females being oviparous (egg layers). Exceptions to these generalizations occur; for example, certain adders (Acanthophis) have commonalities with the Viperidae family, such as shorter, stout bodies, rough/keeled scales, broad heads, cat like pupils and ovoviviparous (internal hatchings with live births). Furthermore, they can also be sluggish, ambush predators with partially fragmented head shields, similar to rattlesnakes or Gaboon vipers. Sea snakes (the Hydrophiinae), sometimes considered to be a separate family, have adapted to a marine way of life in different ways and to various degrees. All have evolved paddle like tails for swimming and the ability to excrete salt. Most also have laterally compressed bodies, their ventral scales are much reduced in size, their nostrils are located dorsally (no internasal scales), and they give birth to live young (viviparity). The reduction in ventral scaling has greatly diminished their terrestrial mobility, but aids in swimming. Members of this family have a wide range of sizes. Drysdalia species are small serpents typically and down to in length. Cobras, mambas, and taipans are mid to large sized snakes which can reach or above. The king cobra is the world's longest venomous snake with a maximum length of and an average mass of .

All elapids have a pair of proteroglyphous fangs to inject venom from glands located towards the rear of the upper jaw (except for the genus Emydocephalus, in which fangs are present as a vestigial feature but without venom production, as they have specialized toward a fish egg diet, making them the only non venomous elapids). The fangs, which are enlarged and hollow, are the first two teeth on each maxillary bone. Usually only one fang is in place on each side at any time. The maxilla is intermediate in both length and mobility between typical colubrids (long, less mobile) and viperids (very short, highly mobile). When the mouth is closed, the fangs fit into grooved slots in the buccal floor and usually below the front edge of the eye and are angled backwards; some elapids (Acanthophis, taipan, mamba, and king cobra) have long fangs on quite mobile maxillae and can make fast strikes. A few species are capable of spraying their venom from forward facing holes in their fangs for defense, as exemplified by spitting cobras.

Most elapids are terrestrial, while some are strongly arboreal (African Pseudohaje and Dendroaspis, Australian Hoplocephalus). Many species are more or less specialized burrowers (e. g. Ogmodon, Parapistocalamus, Simoselaps, Toxicocalamus, and Vermicella) in either humid or arid environments. Some species have very generalised diets (euryphagy), but many taxa have narrow prey preferences (stenophagy) and correlated morphological specializations, for example feeding almost exclusively on other serpents (especially the king cobra and kraits). Elapids may display a series of warning signs if provoked, either obviously or subtly. Cobras and mambas lift their inferior body parts, expand hoods, and hiss if threatened; kraits often curl up before hiding their heads down their bodies. In general, sea snakes are able to respire through their skin. Experiments with the yellow bellied sea snake, Hydrophis platurus, have shown that this species can satisfy about 20% of its oxygen requirements in this manner, allowing for prolonged dives. The sea kraits (Laticauda spp.) are the sea snakes least adapted to aquatic life. Their bodies are less compressed laterally, and they have thicker bodies and ventral scaling. Because of this, they are capable of some land movement. They spend much of their time on land, where they lay their eggs and digest prey.

Terrestrial elapids are found worldwide in tropical and subtropical regions, mostly in the Southern Hemisphere. Most prefer humid tropical environments, though there are many that can still be found in arid environments. Sea snakes occur mainly in the Indian Ocean and the south west Pacific. They occupy coastal waters and shallows, and are common in coral reefs. However, the range of Hydrophis platurus extends across the Pacific to the coasts of Central and South America.

Venoms of species in the Elapidae are mainly neurotoxic for immobilizing prey and defense. The main group of toxins are PLA2 and three finger toxins (3FTx). Other toxic components in some species comprise cardiotoxins and cytotoxins, which cause heart dysfunctions and cellular damage, respectively. Cobra venom also contains hemotoxins which clot or solidify blood. Most members are venomous to varying extents, and some are considered among the world's most venomous snakes based upon their murine values, such as the taipans. Large species, mambas and cobras included, are dangerous for their capability of injecting high quantities of venom upon single envenomation and/or striking at a high position proximal to the victim's brain, which is vulnerable to neurotoxicity. Antivenom is promptly required to be administered if bitten by any elapids. Specific antivenoms are the only cure to treat elapidae bites. There are commercial monovalent and polyvalent antivenoms for cobras, mambas, and some other important elapids. Recently, experimental antivenoms based on recombinant toxins have shown that it is feasible to create antivenoms with a wide spectrum of coverage. The venom of spitting cobras is more cytotoxic rather than neurotoxic. It damages local cells, especially those in eyes, which are deliberately targeted by the snakes. The venom may cause intense pain on contact with the eye and may lead to blindness. It is not lethal on skin if no wound provides any chance for the toxins to enter the bloodstream.