Kamis, 28 Mei 2015

Equatorial spitting cobra (Naja sumatrana) also called the black spitting cobra, Malayan spitting cobra, golden spitting cobra, or Sumatran spitting cobra, is a species of spitting cobra found in Southeast Asia.

Description


Equatorial spitting cobra

This species is medium in length, averaging between 0.9 to 1.2 metres (3.0 to 3.9 ft) in length, though they can grow a bit longer to 1.5 metres (4.9 ft). The body is compressed dorsoventrally and sub-cylindrical posteriorly. The head of this species is elliptical, depressed, and slightly distinct from the neck with a short, rounded snout and large nostrils. Eyes are medium in size with round pupils. Dorsal scales are smooth and strongly oblique. This species of cobra has no hood marks and colouration varies based upon geographical location. There are two colour phases: a yellow form commonly found in Thailand, and a black form found in Peninsular Malaysia, Singapore, and the islands where it occurs in Indonesia and the Philippines. Juveniles and adults also tend to be of different colour.

Scalation

19-27 rows around hood (normally 21-25), 15-19 just ahead of mid-body; 179-201 ventrals, 40-57 subcaudals; basal subcaudals often undivided.

Distribution



This species of cobra is found in the equatorial Southeast Asian nations of Brunei, Indonesia, Malaysia, Singapore, Thailand, and in the Philippines. In Indonesia it occurs in the islands of Sumatra, Borneo, Bangka, Belitung, and the Riau Archipelago. It may occur in neighboring islands in Indonesia. It is possible that remnant populations still occur in western Java. In the Philippines it was thought to be found only in the island province of Palawan but after further DNA study and analysis of the species found in Palawan, it has been established that species endemic to the island is a separate species called the N. miolepis and not a sumatrana.

Habitat and ecology


Equatorial spitting cobra

This species can be found in elevations up to about 1,500 metres (4,900 ft) above sea level in mainly primary and secondary tropical forests (including dense jungle terrain). However, it has also been found in gardens, parks, and in urban areas where it may come in contact with humans. It is a terrestrial and mainly diurnal snake that feeds mainly on rodents and frogs, but will also feed on other snakes, lizards and small mammals. Though not aggressive in nature, these snakes can and will readily spit venom when they are cornered or threatened. They will also strike and bite.

Venom


Equatorial spitting cobra

Like other cobra species, this snake possess postsynaptic neurotoxic venom. The venom may also consist of cardiotoxins and cytotoxins. The venom of the Equatorial spitting cobra exhibited the common characteristic enzymatic activities of Asiatic spitting cobra venoms: low protease, phosphodiesterase, alkaline phosphomonoesterase and L-amino-acid oxidase activities, moderately high acetylcholinesterase and hyaluronidase activities and high phospholipase A2. Cardiotoxins represented 40% of the snakes venom protein. This species presented an IV LD50 of 0.50 µg/g mouse.

References


Equatorial spitting cobra


 
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