New Zealand is well-known for its unique natural environment, and a common question arises regarding the presence of snakes. While the country is largely free of land snakes, its surrounding marine environment occasionally hosts marine snake species. Terrestrial snakes are absent from New Zealand’s landmasses, a status maintained through geological history and rigorous biosecurity measures.
New Zealand’s Terrestrial Snake Status
New Zealand’s lack of native land snakes stems primarily from its ancient geological history and prolonged isolation. Around 82 to 85 million years ago, New Zealand separated from the supercontinent Gondwana, a period predating the significant diversification and global spread of most snake species. This early continental drift meant snakes never naturally colonized the landmass. The vast Tasman Sea acts as a formidable natural barrier, preventing dispersal from landmasses like Australia, which has numerous snake species.
New Zealand’s cooler climate is also unsuitable for many snake species, which thrive in warmer environments. No credible fossil evidence indicates snakes were ever native to New Zealand. While an isolated fossil resembling a python was discovered in 2002, dating back 15 to 20 million years, this singular finding does not suggest an established native population.
Marine Snakes in New Zealand Waters
Despite the absence of land snakes, New Zealand’s waters occasionally host marine snake species, though these are rare visitors. The yellow-bellied sea snake is the most commonly sighted, with around 6 to 10 individuals reported annually, primarily along the North Island’s northeast coast. The yellow-lipped sea krait is observed less frequently. These sea snakes are highly venomous but generally docile, with small fangs that make biting humans rare.
Marine snakes spend their entire lives at sea. Those found in New Zealand waters often arrive unintentionally, carried by ocean currents or storms from warmer tropical regions. New Zealand’s cooler water temperatures are typically too cold for their long-term survival, meaning many that wash ashore are already unwell and unlikely to survive. Unlike land snakes, these marine species do not establish breeding populations on New Zealand’s land, as even sea kraits, which require land for laying eggs, find the climate unsuitable for reproduction. All sea snakes and kraits are protected under New Zealand’s Wildlife Act 1953.
Preventing Snake Incursions and Common Misconceptions
New Zealand’s snake-free status on land is preserved through comprehensive biosecurity measures. Biosecurity New Zealand implements a multi-layered system including strict import requirements, thorough border checks, and ongoing surveillance at ports and airports to intercept potential stowaways. These efforts are important for preventing the establishment of terrestrial snake populations, which could impact the country’s unique native wildlife.
The public plays a role in these biosecurity efforts. Any suspected snake sighting should be immediately reported to authorities by calling 0800 DOC HOT. It is illegal to kill, harass, or possess a sea snake without a permit.
A common misconception involves mistaking native legless lizards, such as geckos and skinks, for snakes. However, these reptiles have distinct characteristics: lizards possess eyelids, external ear openings, and a fleshy tongue, while snakes lack these features and have a forked tongue. Lizards also have a solid lower jawbone, unlike the flexible, two-part jaw of a snake. Knowing these differences helps ensure proper identification if an unusual reptile is encountered.