Philippine cobra

Identification

The Philippine cobra is a medium-sized cobra with smooth scales and round pupils². Adults are plain light brown to olive brown above and cream to yellowish brown below, with no bands or other markings on the front of the body^2,3,4. Some adults are a uniform dark grey³. Young snakes look quite different: they are dark brown to black, covered with a network of light olive-yellow⁴. Like other cobras, it rears up and spreads a hood when alarmed⁴.

The adult female that Taylor used to describe this cobra in 1922 was 1.0 m long⁴. The largest on record is a male of about 1.41 m: 1.22 m from snout to vent, plus a 19 cm tail².

Distribution

This cobra is found only in the northern Philippines, on Luzon, Mindoro, Masbate, Marinduque, Catanduanes and Lubang^1,3. It was first described in 1922 as a subspecies of the Indian cobra, Naja naja philippinensis, and is now treated as a species of its own^1,4. The southern Philippines have a different cobra, the Samar cobra (Naja samarensis), and Palawan has the equatorial spitting cobra (Naja sumatrana)². In the Sierra Madre of north-eastern Luzon it appears to be widespread and common⁵.

Habitat

The Philippine cobra is often found on farmland and around villages^3,5. In north-eastern Luzon, cobras have been found hiding on agricultural land, and one was probably caught by residents in farmland around a settlement^3,5. The dangerously venomous land snakes of the Philippines can all swim, and some regularly live near houses, on farms and around water such as flooded rice fields, rivers and streams². Cobra bites are an important cause of death among rice farmers⁸.

Behaviour

This is a spitting cobra: when threatened it can spray venom towards an attacker’s eyes^3,6. It also rears up, spreads its hood and hisses⁴. In captivity, hatchlings did this before they had even left the egg, rearing up with the hood spread to hiss and strike at nearby objects⁴. Cobras found near homes and fields are often killed by local people^3,5.

Diet

In captivity in the early 1900s, some cobras readily took frogs and small snakes, while others refused all food⁴. Newly hatched young did not eat until after their first shed of skin⁴.

Reproduction

The Philippine cobra lays eggs¹. One captive female laid 12 eggs, which hatched after about seven weeks in moist earth⁴. The hatchlings stayed partly inside their eggs for three or four days before leaving them⁴.

Venom and medical significance

The Philippine cobra is dangerously venomous. In a study of 39 people envenomed by this cobra, 38 developed signs of nerve poisoning, and 19 developed paralysis of the breathing muscles, in 3 cases within 30 minutes of the bite⁷. Swelling was usually slight, though 3 people developed tissue death (necrosis), and 14 people with serious general symptoms had no local swelling at all⁷. Its venom is almost purely neurotoxic, which is unusual for a spitting cobra⁶.

A study published in 1987 estimated that cobra bites killed up to 107 people per 100,000 each year in one rice-farming area, and only 8% of the victims studied had reached a hospital⁸. A specific antivenom, Philippine Cobra Antivenom, is made in the Philippines by the Research Institute for Tropical Medicine, and it is the only antivenom produced in the country^9,10. Anyone bitten should go to hospital immediately.

Conservation

The Philippine cobra is listed as Near Threatened on the IUCN Red List (assessed in 2022)¹¹. Persecution and exploitation by people have been identified as possible threats⁵. Cobras found near homes are often killed by residents³.

Similar species

The Samar cobra (Naja samarensis) of the southern Philippines is darker, with a few pale yellow belly scales behind the head followed by a black band². The equatorial spitting cobra (Naja sumatrana) lives on Palawan and Culion, outside the Philippine cobra’s range². Luzon is also home to the Luzon king cobra (Ophiophagus salvatana)¹². King cobras have no more than 15 rows of scales around the middle of the body, while the Philippine cobra has 21–23². These differences are not a safe basis for handling any snake. Keep your distance from every snake you cannot identify.

In captivity

The Philippine cobra is a dangerous venomous snake and is not suitable as a pet. Cobras are kept at the antivenom production facility of the Research Institute for Tropical Medicine³, and in the early 1900s they were kept in Manila to collect venom for making antivenom⁴. They should never be caught or kept by private individuals.