Guwahati: A study led by a group of Mizoram researchers has provided the first comprehensive morphological characterisation of the Northern King Cobra population in Mizoram, while reinforcing earlier genetic evidence placing the state’s king cobras within the Indo-Chinese lineage, Ophiophagus hannah.
The study, led by Prof. Hmar Tlawmte Lalremsanga of the Department of Zoology, Mizoram University, has been published in Proceedings of the Zoological Society by Springer.
Despite the difficulty in obtaining data for the species due to being a highly protected species in India (Schedule 1 animal) and vulnerable species as per IUCN, researchers examined 27 adult king cobras—15 males and 12 females, combining detailed morphological measurements with mitochondrial DNA analysis to examine the population’s systematic placement.
The specimens included 14 preserved snakes and 13 live individuals examined during herpetological surveys conducted between 2007 and 2023.
The molecular analysis used three mitochondrial markers—16S rRNA, cytochrome c oxidase subunit 1 (cox1) and cytochrome b (cytb). The resulting phylogenetic analysis placed the Mizoram samples within the Indo-Chinese lineage, alongside populations from Northeast India and other parts of the region.
The finding adds morphological evidence to earlier genetic studies that had already placed Mizoram’s king cobras within O. hannah. Until now, the researchers said, detailed morphological assessment of the Mizoram population had been lacking.
The study comes amid a major revision in the understanding of king cobra diversity. The researchers note that what was once treated as a widespread single species is now recognised as four distinct evolutionary lineages or species: the Indo-Chinese O. hannah, Western Ghats O. kaalinga, Indo-Malayan O. bungarus and Luzon Island O. salvatana.
The Mizoram snakes showed measurable differences between males and females. Females had a higher mean number of ventral scales, while males recorded higher mean values for subcaudal scales, undivided subcaudals, tail length and several head measurements. These included head length, head width, head depth, nostril diameter, internarial space, frontal width and parietal width.
The researchers suggest that the differences in head size and shape merit further investigation, including whether they may be associated with sex-specific sexual selection and male-male rivalry. They stress that this remains a question for future research rather than a conclusion established by the present study.
The researchers also updated several previously reported morphological ranges for the species. The Mizoram specimens showed, among other characteristics, 236–261 ventral scales in males and 240–258 in females, while male tail lengths ranged from 300 to 630 mm and female tail lengths from 308 to 430 mm.
The study, however, points to limitations in some of these updated ranges. Two unusually high measurements came from live rescued snakes that were released after data collection and therefore could not be re-examined. The authors say the differences could reflect habitat adaptation, thermal conditions during development or sampling variation.
The researchers said the new morphological and genetic information provides baseline data for future work on the evolution, systematics and conservation of king cobras in Mizoram.
The study also highlights conservation concerns.
King cobras are frequently killed following encounters with people, while habitat destruction, retaliatory killings and the destruction of nesting sites have been identified as threats to the northern king cobra population in the region. The authors argue that distinct evolutionary lineages may require conservation strategies tailored to the threats they face.