New Zealand is widely recognized for its unique natural environment, often prompting questions about the presence of snakes. The country does not have any native terrestrial snake species. This distinct characteristic is a defining feature of its ecology, setting it apart from many other landmasses globally.
The Absence of Native Terrestrial Snakes
New Zealand’s lack of native land snakes is primarily attributed to its ancient geological history and prolonged isolation. The landmass separated from the supercontinent Gondwana approximately 85 million years ago, a period predating the widespread diversification and global dispersal of most modern snake species. This early separation meant that snakes simply never had the opportunity to naturally colonize the islands.
The vast oceanic distances surrounding New Zealand after its continental drift formed an insurmountable natural barrier. This geographical isolation prevented any subsequent natural migration of terrestrial snakes to the islands. Although a fossilized snake, similar to a python and estimated to be 15 to 20 million years old, was once found, indicating their prehistoric presence, these species did not persist to modern times.
Marine and Accidental Visitors
Certain marine snake species occasionally visit New Zealand’s waters. The yellow-bellied sea snake (Pelamis platurus) is the most frequently sighted. These fully aquatic snakes are carried by warm ocean currents and typically wash ashore when they are ill or impacted by storms.
Sea kraits are also occasional visitors to New Zealand’s waters. Unlike yellow-bellied sea snakes, kraits are semi-aquatic and spend some time on land to drink fresh water and lay eggs. Despite their occasional presence, breeding populations of sea snakes or kraits are not established in New Zealand’s cooler waters. All sea snakes and kraits are highly venomous but are generally docile, and there are no recorded instances of them biting humans in New Zealand. These species are considered native under the Wildlife Act 1953 because they arrive naturally via ocean currents, making it illegal to harm them.
Beyond marine visitors, there are rare instances of terrestrial snakes arriving accidentally in New Zealand, typically as stowaways on cargo ships or planes. These accidental arrivals do not lead to established wild populations due to New Zealand’s climate and stringent biosecurity responses.
Protecting New Zealand’s Borders
New Zealand maintains a robust biosecurity system aimed at preventing the establishment of non-native species, including snakes. The Ministry for Primary Industries (MPI) spearheads these efforts under the Biosecurity Act 1993. This comprehensive system includes strict import regulations, thorough border inspections, and continuous post-border surveillance.
Trained personnel are in place to manage any detections safely and effectively. Public vigilance is also an important component of the biosecurity strategy, with citizens encouraged to report any suspected snake sightings immediately to authorities like the Department of Conservation (DOC) or Biosecurity New Zealand. Any terrestrial snakes found are typically euthanized to eliminate any risk of them establishing a breeding population.
New Zealand’s Unique Reptile Fauna
Despite the absence of native terrestrial snakes, New Zealand is home to a distinctive array of native reptiles. These include various species of geckos, skinks, and the ancient tuatara. The tuatara, a lizard-like reptile, is the sole surviving member of an order of reptiles that thrived alongside dinosaurs approximately 220 million years ago, making it a unique “living fossil.”
New Zealand boasts a remarkable diversity of geckos, with at least 17 species, and numerous skinks, including 28 endemic species, and a total of 126 described lizard species. The vast majority of these native lizards are endemic, meaning they are found nowhere else in the world. All native lizards are fully protected under the Wildlife Act 1953. Conservation efforts for these reptiles primarily focus on mitigating threats from introduced mammalian predators and habitat destruction.