Monocled Cobra

Fascinating facts about the Monocled Cobra

• When René Lesson first described the monocled cobra in 1831, he noted it had exactly 188 ventral scales and 53 pairs of caudal scales – a fingerprint that still helps herpetologists tell it apart from its cousins. Those scale counts reveal how subtle anatomy can define an entire species.
• Adult monocled cobras usually grow to 1.35–1.5 m (4.4–4.9 ft), but rare giants can reach 2.3 m (7.5 ft), showing that even a “typical” size range hides extraordinary outliers in the wild.
• A single bite can deliver about 263 mg of dry-weight venom, enough to cause flaccid paralysis within an hour and make this snake the leading cause of snakebite deaths in Thailand. That tiny amount underscores how lethal a well-evolved neurotoxin can be.
• Females lay 16–33 eggs per clutch and incubate them for 55–73 days, a relatively long parental investment for a reptile, highlighting that even venomous snakes can be diligent parents.
• In Thailand, intravenous LD₅₀ values as low as 0.18 µg/g have been recorded, while in Malaysia and Vietnam the same test yields 0.90–1.11 µg/g, illustrating dramatic regional differences in venom potency that challenge one-size-fits-all antivenom strategies.

At a glance

About the Monocled Cobra

The monocled cobra, Naja kaouthia, is instantly recognizable by the striking O-shaped “monocle” on its hood, a contrast to the Indian cobra’s paired spectacles. Its dorsal palette shifts from yellow, brown, gray to almost black, often bearing ragged cross-bands, while the ventral side mirrors the back’s hue but paler, punctuated by a black spot on each side of the lower hood and one or two black cross-bars on the belly. Adults typically measure 1.35–1.5 m, with rare giants reaching 2.3 m, and sport 25–31 neck scales, 164–197 ventrals, and 43–58 subcaudals. This terrestrial predator thrives from the paddy fields, swamps, and mangroves of South and Southeast Asia to grasslands, shrublands, forests, and even bustling cities up to 1,000 m elevation, favoring water-adjacent habitats. At dusk it emerges from rodent burrows in rice-dykes, hunting amphibians as a juvenile and shifting to small mammals, fish, and other snakes as an adult. When threatened it raises its forebody, spreads its iconic hood, hisses, and may strike, but some populations add a startling twist: they can accurately spit venom, earning the moniker “Indian spitting cobra.”

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