Tiger Keelback

The Tiger Keelback, known in Japan as Yamakagashi, is a rear-fanged colubrid widespread across East Asia. It is notable in herpetology for possessing both venom glands in the mouth and specialized nuchal glands along the neck that store toxins sequestered from toad prey.

Although long regarded as harmless due to its rear-fanged bite, several documented cases have shown its venom can cause serious, even fatal, effects, making it one of the more medically important colubrids known.

• Olive to greenish-brown body with irregular reddish-orange and black blotches, especially pronounced toward the front third
• Pattern fades in some populations, giving a more uniform brownish appearance
• Keeled dorsal scales
• Head slightly distinct from neck, round pupils
• Adults typically 0.7-1.5 m in length

Found in rice paddies, marshes, grasslands, and forest edges near water across Japan, the Korean Peninsula, mainland China, and parts of the Russian Far East. It favors humid lowland and hilly habitats close to amphibian breeding sites.

Diurnal and semi-aquatic, feeding heavily on frogs and toads. When threatened it may arch and flatten its neck to display the nuchal gland area rather than strike immediately. It is oviparous, with females laying clutches of roughly 10-40 eggs depending on body size and region.