The Equatorial spitting cobra (''Naja sumatrana'') also called the Malayan spitting cobra, golden spitting cobra, Sumatran spitting cobra, or Palawan spitting cobra, is a species of

spitting cobra A "spitting" cobra is any of several species of cobra that can intentionally, defensively shoot their snake venom, venom directly from their fangs. This substance has two functions, with the first being as venom that can be absorbed via the vict ...

found in

Southeast Asia Southeast Asia is the geographical United Nations geoscheme for Asia#South-eastern Asia, southeastern region of Asia, consisting of the regions that are situated south of China, east of the Indian subcontinent, and northwest of the Mainland Au ...

Description

This species is medium in length, averaging between in length, though they can grow up to . 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 Northern Peninsular Malaysia, 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 the hood (normally 21–25), 15-19 just ahead of the mid-body; 179-201 ventrals, 40-57 subcaudals; basal subcaudals are often undivided.

Taxonomy

The population currently included in ''Naja sumatrana'' have a confusing history. The species was first defined as currently understood in 1989. Previously, the populations of this species were assigned to several different subspecies of ''Naja naja'' (

Indian cobra The Indian cobra (''Naja naja /na''dʒa nadʒa/), also known Common name, commonly as the spectacled cobra, Asian cobra, or binocellate cobra, is a species of Naja, cobra, a venomous snake in the Family (biology), family Elapidae. The species is ...

), in particular ''N. n. sumatrana'' (Sumatra), ''N.n. sputatrix'' (Peninsular Malaysia) and ''N.n. miolepis'' (Borneo, Palawan). Some confusion over names has persisted into the more recent toxinological literature, in particular the misapplication of the name ''sputatrix'' to venoms of ''Naja sumatrana'' from Peninsular Malaysia.

Distribution

This species of cobra is found in the equatorial

n nations of

Brunei Brunei, officially Brunei Darussalam, is a country in Southeast Asia, situated on the northern coast of the island of Borneo. Apart from its coastline on the South China Sea, it is completely surrounded by the Malaysian state of Sarawak, with ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

Malaysia Malaysia is a country in Southeast Asia. Featuring the Tanjung Piai, southernmost point of continental Eurasia, it is a federation, federal constitutional monarchy consisting of States and federal territories of Malaysia, 13 states and thre ...

Singapore Singapore, officially the Republic of Singapore, is an island country and city-state in Southeast Asia. The country's territory comprises one main island, 63 satellite islands and islets, and one outlying islet. It is about one degree ...

Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...

, and in the

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

. In Indonesia it occurs on the islands of

Sumatra Sumatra () is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the list of islands by area, sixth-largest island in the world at 482,286.55 km2 (182,812 mi. ...

Borneo Borneo () is the List of islands by area, third-largest island in the world, with an area of , and population of 23,053,723 (2020 national censuses). Situated at the geographic centre of Maritime Southeast Asia, it is one of the Greater Sunda ...

, Bangka,

Belitung Belitung (Belitung Malay: ''Belitong'', formerly Billiton) is an island on the east coast of Sumatra, Indonesia in the Java Sea. It covers (including offshore islands such as Mendanau Island), and had a population of 309,097 at the 2020 Cen ...

, and the

Riau Archipelago The Riau Archipelago is a ''geographic'' term (as opposed to administrative region) for the core group of islands within the Riau Islands Province in Indonesia, and located south of Singapore and east of Riau on Sumatra. Before the province of Ri ...

. It may occur on neighboring islands in Indonesia, and it is possible that remnant populations still occur in western

Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...

. In the

, it only occurs in the

Palawan Palawan (, ), officially the Province of Palawan (; ), is an archipelagic province of the Philippines that is located in the region of Mimaropa. It is the largest province in the country in terms of total area of . The capital and largest c ...

group of islands (including the

Calamian Islands The Calamian Islands or the Calamianes is a group of islands in the province of Palawan, Philippines. It includes: * Busuanga Island * Coron Island * Culion Island * Calauit Island * Malcapuya Island * Banana Island * Pass Island * Calumbuyan ...

Habitat and ecology

This species can be found in elevations up to about 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 too aggressive in nature, these snakes can and will readily spit venom, even from up in the trees, when they are cornered or threatened. They will also strike and bite.

Venom

Like other cobra species, this snake possesses postsynaptic

neurotoxic Neurotoxicity is a form of toxicity in which a biological, chemical, or physical agent produces an adverse effect on the structure or function of the central and/or peripheral nervous system. It occurs when exposure to a substance – specifical ...

venom. The venom also consists of

cardiotoxin Cardiotoxicity is the occurrence of heart dysfunction as electric or muscle damage, resulting in heart toxicity. This can cause heart failure, arrhythmia, myocarditis, and cardiomyopathy in patients. Some effects are reversible, while in others, p ...

s and

cytotoxin Cytotoxicity is the quality of being toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium ...

s. Although the venom of the Equatorial spitting cobra (''N. sumatrana'') exhibited the common characteristic enzymatic activities of Asiatic spitting cobra venoms, the protein composition of the Equatorial spitting cobra venom is distinct from venoms of the other two

sympatric In biology, two closely related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter each other. An initially interbreeding population that splits into two or more distinct spe ...

spitting cobras, the

Javan spitting cobra The Javan spitting cobra (''Naja sputatrix''), also called Indonesian cobra or Komodo spitting cobra, is a species of cobra in the family Elapidae, found in the Lesser Sunda Islands of Indonesia, including Java, Bali, Lombok, Sumbawa, Flores, K ...

(''N. sputatrix'') and Indochinese spitting cobra (''N. siamensis''). However, this species' venom contains low

protease A protease (also called a peptidase, proteinase, or proteolytic enzyme) is an enzyme that catalysis, catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products ...

phosphodiesterase A phosphodiesterase (PDE) is an enzyme that breaks a phosphodiester bond. Usually, ''phosphodiesterase'' refers to cyclic nucleotide phosphodiesterases, which have great clinical significance and are described below. However, there are many oth ...

, alkaline phosphomonoesterase and

L-amino-acid oxidase In enzymology, an L-amino acid oxidase (LAAO) () is an enzyme that catalyzes the chemical reaction: :an L-amino acid + H2O + O2 \rightleftharpoons a 2-oxo acid + NH3 + H2O2 The enzyme was first described in 1944 by A. Zeller and A. Maritz. Not o ...

activities, moderately high

acetylcholinesterase Acetylcholinesterase (HUGO Gene Nomenclature Committee, HGNC symbol ACHE; EC 3.1.1.7; systematic name acetylcholine acetylhydrolase), also known as AChE, AChase or acetylhydrolase, is the primary cholinesterase in the body. It is an enzyme th ...

and

hyaluronidase Hyaluronidases are a family of enzymes that catalyse the degradation of hyaluronic acid. Karl Meyer classified these enzymes in 1971, into three distinct groups, a scheme based on the enzyme reaction products. The three main types of hyaluroni ...

activities and high phospholipase A₂. Cardiotoxins represented 40% of the snake's venom protein, higher than sympatric cobras: ''N. sputatrix'' (35%), ''N. siamensis'' (30%), and ''N. kaouthia'' (18%; non-spitting cobra). This species presented an IV of 0.5 mg/kg (Malaysia).

References

{{Taxonbar, from=Q584649 Naja Snakes of Southeast Asia Reptiles of the Philippines Reptiles described in 1890 Reptiles of Borneo