The King Cobra, Ophiophagus hannah, is an iconic reptile known for its imposing length and powerful presence. This serpent is the undisputed champion of size among all venomous snake species.
The Record-Breaking Dimensions
The title of the biggest King Cobra ever recorded belongs to a specimen captured in April 1937 near Port Dickson in Negeri Sembilan, Malaysia. This male snake was transferred to the London Zoo, where it continued to grow under observation. By the autumn of 1939, this individual was officially measured at a length of 5.71 meters (18 feet 8 inches), establishing the standing record for the longest venomous snake in the world. While the exact weight of this record-holder is not consistently documented, the heaviest reliably recorded King Cobras have weighed up to 12.7 kilograms (28 pounds), placing them among the heaviest venomous snakes known.
Distinguishing Features of the King Cobra
The average length for a mature adult King Cobra is typically between 3.18 and 4 meters (10.4 and 13.1 feet). The species exhibits sexual dimorphism, with males generally growing larger than females of a comparable age. This difference explains why the record-breaking specimens are almost always male. Despite its enormous length, the King Cobra maintains a relatively slender body compared to non-venomous constrictors like pythons, which achieve greater weight and girth. Its imposing size is complemented by a narrow, elongated hood that it displays during a threat posture, a feature distinct from the broader hood of true cobras in the Naja genus.
Regional Differences in Maximum Size
King Cobras are distributed across a wide geographic range throughout South and Southeast Asia, and their maximum size varies significantly by region. The species is now understood to be a species complex, with distinct lineages identified in different locations. Specimens from mainland Southeast Asia, such as Thailand and Malaysia, are generally known to reach the greatest average and maximum lengths, including the record-holder from Malaysia. Conversely, King Cobras found in insular regions, like the Western Ghats of India or the island of Luzon in the Philippines, tend to be smaller on average. This size variation is often correlated with environmental factors. Areas with dense, undisturbed forest cover and a consistent, abundant supply of prey—primarily other snakes—provide the necessary resources for individuals to achieve their maximum potential size. The King Cobra’s highly specialized diet is a factor that dictates the overall biomass and length an individual can attain within its local habitat.