Monocled cobra
The monocled cobra ("Naja kaouthia"), also called monocellate cobra, or Indian spitting cobra, is a venomous cobra species widespread across South and Southeast Asia and listed as Least Concern on the IUCN Red List. Taxonomy. The scientific name "Naja kaouthia" was proposed by René Lesson in 1831, when he described the monocled cobra as a beautiful snake that is distinct from the spectacled cobra, with 188 ventral scales and 53 pairs of caudal scales. Since then, several monocled cobras were described under different scientific names: Several varieties of monocled cobras were described under the binomial "Naja tripudians" between  1895 and 1913: In 1940, Malcolm Arthur Smith classified the monocled cobra as a subspecies of the spectacled cobra under the trinomial "Naja naja kaouthia". Reclassification in the 1990s further distinguished "Naja kaouthia" from "Naja siamensis", a name commonly used in older toxinological research. Phylogenetic studies of "Naja kaouthia" in Thailand have demonstrated surprising variation, with one population resulting in the species becoming paraphyletic with other Asiatic cobras. Characteristics. The monocled cobra has an O-shaped, or monocellate hood pattern, unlike that of the Indian cobra, which has the "spectacle" pattern (two circular ocelli connected by a curved line) on  the rear of its hood. The elongated nuchal ribs enable a cobra to expand the anterior of the neck into a “hood”. Coloration in the young is more constant. The dorsal surface may be yellow, brown, gray, or blackish, with or without ragged or clearly defined cross bands. It can be olivaceous or brownish to black above with or without a yellow or orange-colored, O-shaped mark on the hood. It has a black spot on the lower surface of the hood on either side, and one or two black cross-bars on the belly behind it. The rest  of the belly is usually the same color as the back, but paler. As age advances, the snake becomes paler, wherein the adult is brownish or olivaceous. A pair of fixed anterior fangs is present. The largest fang recorded measured . Fangs are moderately adapted for spitting. Adult monocled cobras reach a length of with a tail length of . Many larger specimens have been recorded, but they are rare. Adults can reach a maximum of in length. Scalation. The monocled cobra has 25 to 31 scales on the neck, 19 to 21 on the body, and 17 or 15 on the  front of the vent. It has 164 to 197 ventral scales and 43 to 58 subcaudal scales. It typically has more than one cuneate scale on each side. The shape of the frontal scale is short and square. Ventrals in males range from 170 to 192, in females from 178 to 197. Subcaudals in males range from 48 to 61, in females from 46 to 59. Distribution and habitat. The monocled cobra is distributed from India in the west through to China, Vietnam and Cambodia. It also occurs on the Malay Peninsula and is native to West Bengal, Bangladesh, Bhutan , Myanmar, Laos, Nepal, and Thailand. It can adapt to a range of habitats, from natural to anthropogenically impacted environments. It prefer habitats associated with water, such as paddy fields, swamps and mangroves, but lives also in grasslands, shrublands, forests, agricultural land at elevations of up to and human settlements including cities. Ecology and behaviour. Monocled cobras are terrestrial and most active at dusk. In rice-growing areas, they hide in rodent burrows in the dykes between fields and have become semi-aquatic in this type of habitat. Juveniles feed mostly on amphibians whereas adults prey on small mammals, snakes and  fish. When disturbed they prefer to take flight. However, when threatened they will raise the anterior portions of their bodies, spread their hood, usually hiss loudly, and strike in an attempt to bite and defend themselves. They are often found in tree holes and areas where rodents are plentiful. Some populations of the monocled cobra have the ability to spit venom, earning them the name "Indian spitting cobra". Reproduction. This is an oviparous species. Females lay 16 to 33 eggs per clutch. Incubation periods range from 55 to 73 days. Egg-laying takes place January through March. The females usually  stay with the eggs. Some collaboration between males and females has been reported in "Naja naja" x "Naja kaouthia" - hybrids. Conservation status. The monocled cobra is listed on CITES Appendix II and has been assessed as Least Concern on the IUCN Red List due to its large distribution, tolerance of a broad range of habitats including anthropogenically altered environments, and its reported abundance. No major threats have been reported, and it is not thought to be undergoing a significant population decline. Monocled cobras are harvested for the wildlife trade, however, collection from the wild is minimal and not likely to  cause significant population declines. Venom. The venom of the monocled cobra from three different localities were reported to exhibit different intravenous and subcutaneous median lethal dose: Thailand, 0.18-0.22 µg/g; Malaysia, 0.90-1.11 µg/g; and Vietnam, 0.90-1.00 µg/g, of mouse body weight. These results reflect the distinct difference in the lethal potency of the monocled cobra and response to antivenom neutralization. The major toxic components in cobra venoms are postsynaptic neurotoxins, which block the nerve transmission by binding specifically to the nicotinic acetylcholine receptor, leading to flaccid paralysis and even death by respiratory failure. The major  α-neurotoxin in the monocled cobra's venom is a long neurotoxin, α-cobratoxin; the minor α-neurotoxin is different from cobrotoxin in one residue. The neurotoxins of this particular species are weak. The venom of this species also contains myotoxins and cardiotoxins. In case of intravenous injection the tested in mice is 0.373 mg/kg, and 0.225 mg/kg in case of intraperitoneal injection. The average venom yield per bite is approximately 263 mg dry weight. The monocled cobra causes the highest fatality due to snake venom poisoning in Thailand. Envenomation usually presents predominantly with extensive local necrosis and  systemic manifestations to a lesser degree. Drowsiness, neurological and neuromuscular symptoms will usually manifest earliest; hypotension, flushing of the face, warm skin, and pain around bite site typically manifest within one to four hours following the bite; paralysis, ventilatory failure or death could ensue rapidly, possibly as early as 60 minutes in very severe cases of envenomation. However, the presence of fang marks does not always imply that envenomation actually occurred. In a preliminary study, extract of Mimosa pudica plant has been shown to possibly have neutralizing effects on the toxins present in this venom.