More king cobra species than previously known

The King Cobra, the world's largest venomous snake, is not just one species. There are at least three more, according to Uppsala University and other researchers, who have analysed DNA from, and studied physical traits of, individuals from virtually the whole of the reptile's range.

"We were surprised to find such clear differences. What have been considered a single species to date are several distinct, geographically separated groups that don't reproduce with one another," says Jacob Höglund, Professor of Animal Conservation Biology at the Department of Ecology and Genetics, who took part in the study.

One of these King Cobra groups is found along the southwest coast of India. Another has a range that extends east from the Himalayas through India, China and Thailand to Vietnam. The third group is spread across Indonesia, Malaysia and the Philippines, while the fourth lives only on the Philippine island of Luzon. They all have a common origin, but have been genetically isolated and distanced from each other owing to geographical barriers, such as rising sea levels or areas that have become too arid for them to thrive in.

Variations in colours and body size

In appearance, the various groups are fairly similar. Nevertheless, there are variations in colour and body size, for example. Whether this is caused by mutations or due to the snakes' habitats, researchers cannot answer at present.

It has long been known that the King Cobra's venom, which attacks the victim's nervous system, varies widely from one population to another. The new knowledge that the King Cobra is not a homogeneous species but, rather, the culminations of several distinctive genetic lines of evolution may therefore have a significant bearing on scientists' ability to develop serum for treating the bites. The researchers therefore need to identify the genes that control the venom production.

"Gowri Shankar, the main author of the article, told me that commercial snake serum is available in Thailand, but it doesn't work in India. So today, there's no snake serum against the King Cobra's venom in India," Höglund says.

Cryptic species

If further studies confirm that there are indeed several King Cobra species, they would be "cryptic" – the term for what is thought to be one but turns out to be two or more distinctly different, "hidden" species. From a conservation point of view, this is vital knowledge.

"Because of the existing differences, a species that's dying out can't be saved by translocating snakes from other areas. Another issue connected with cryptic species, for example, is whether closely related species can hybridise. Other factors affect translocation, too; for example, there may be various adaptations that do not work in the habitat concerned. What we're anxious to create is good biodiversity that can preserve unique lines of evolution, irrespective of whether they are separate species," Höglund says.

The greatest threat to the King Cobra is habitat loss, not least because of oil palm plantations, which destroy natural biodiversity. The King Cobra population of Luzon is particularly vulnerable, since it is so geographically restricted.

The four genetic groups of King Cobra have not yet been given the official status of species, or even subspecies, in their own right. If this happens, it will be a lengthy process, starting with them being formally described in a scientific journal.

Åsa Malmberg