Hawaii is known for its pristine beaches, lush landscapes, and a unique ecological characteristic: the absence of native terrestrial snakes. While occasional introductions mean the islands are not entirely snake-free, the state maintains a strong stance against their establishment to protect its delicate natural environment.
Hawaii’s Unique Snake-Free Status
The Hawaiian Islands’ geological history explains their lack of native snake species. Formed by volcanic activity far from continental landmasses, the islands emerged from the ocean floor without land bridges. This extreme isolation meant most terrestrial animals, including snakes, could not naturally reach or establish populations.
Hawaii’s ecosystems evolved in the absence of snake predators. This resulted in native wildlife, particularly ground-nesting birds, that lack natural defenses. The Brahminy blind snake, a small, worm-like introduced species, is now widespread but harmless to the native ecosystem. The yellow-bellied sea snake is an aquatic species occasionally seen in Hawaiian waters, but it rarely comes ashore.
The Invasive Snake Threat
Despite Hawaii’s snake-free status for native land species, invasive snakes pose a serious concern. The brown tree snake (Boiga irregularis) is the most significant potential threat due to its devastating impact on Guam. This nocturnal, mildly venomous snake, native to parts of the Indo-Pacific, was accidentally introduced to Guam after World War II, likely via military transports. On Guam, it caused the extinction of 9 out of 11 native forest bird species and many lizard species, with population densities reaching up to 30,000 per square mile.
The brown tree snake’s presence on Guam has also led to significant economic damage, including thousands of power outages caused by snakes climbing on electrical lines. If established in Hawaii, the brown tree snake could cause billions of dollars in damage annually and decimate Hawaii’s unique bird populations, which have no defenses against such a predator. While no established population exists in Hawaii, eight brown tree snakes were found live or dead between 1981 and 1998, all linked to cargo from Guam.
Beyond the brown tree snake, various other non-native snake species have been intercepted in Hawaii, typically as stowaways on cargo or through illegal smuggling. These include ball pythons, boa constrictors, garter snakes, gopher snakes, and corn snakes. These sightings are generally isolated incidents, and authorities quickly capture and remove the animals to prevent them from establishing breeding populations.
Strict Biosecurity Measures
Hawaii implements stringent biosecurity measures to prevent the entry and establishment of invasive snakes. The Hawaii Department of Agriculture (HDOA) and other agencies work collaboratively to enforce strict inspection protocols at all ports of entry, including airports and harbors. Incoming cargo, luggage, and vehicles are thoroughly inspected to detect potential stowaways.
A key component of these efforts is the Hawaii Detector Dog Program, which employs specially trained canines, often Jack Russell terriers, to sniff out hidden snakes. These dogs are trained to detect brown tree snakes, but their generalized training allows them to identify other snake species. The HDOA also operates an amnesty program, encouraging individuals who possess illegal animals, including snakes, to surrender them without facing criminal charges or fines if done before an investigation begins.
Reporting Snake Sightings
The public plays a role in maintaining Hawaii’s snake-free status by promptly reporting any snake sightings. If an individual encounters a snake in Hawaii, it is advised not to approach or attempt to handle the animal. Instead, the sighting should be reported immediately to the appropriate authorities.
The statewide pest hotline, 643-PEST (808-643-7378), is the primary contact for reporting invasive species, including snakes. An online reporting system is also available at 643pest.org, where individuals can pinpoint the sighting on a map and provide details. For immediate snake sightings, especially if the snake is large or appears dangerous, contacting 911 is recommended. Quick reporting allows authorities to respond swiftly, contain the animal, and prevent potential establishment in the environment.