Hawaii Dangerous Wildlife

Box Jellyfish. Transparent box jellyfish swarm to Hawaii’s leeward shores a week or so after the full moon. A jellyfish can measure 1-3 in. with tentacles of up to 2 ft. long. Its painful sting can sometimes cause anaphylactic shock. If you are stung, apply vinegar to the sting and then pluck any tentacles out of the affected area using tweezers, a towel, or cloth (avoid using your bare hands). Make sure it is in fact a jellyfish sting, as using vinegar on Portuguese Man-of-War stings (see below) is potentially dangerous. Never rub the affected area or use freshwater, as the tentacles can release more venom even after detached from the jellyfish. Contrary to popular belief, there is little proof that urinating on your sting is helpful and will probably just leave you a little more messy. If you are at all concerned about the sting seek medical care.

Portuguese Men-Of-War. Not technically a jellyfish (though it resembles one), the Portuguese Man-of-War (also known as a bluebottle) packs an excruciatingly painful sting. Purplish-blue in color with tentacles up to 33 ft. long., the Portuguese Man-of-War’s sting can cause anaphylactic shock, interference with heart and lung function, and even death. Do not, under any circumstances, apply vinegar to a sting from a Portuguese Man-of-War. Instead, rinse the sting with saltwater or freshwater and apply a cold or hot compress to the affected area. Do not rub the affected area. Be careful on the beach as well—Portuguese Men-of-War carcasses and detached tentacles can still sting. If pain persists or if breathing difficulty develops, consult a medical professional immediately.

Better Safe Than Sorry. While we list the tried-and-true treatments for jellyfish and Portuguese Men-of-War stings, you should always seek medical care if you are at all worried about an injury.

Sharks. About 40 species of sharks inhabit Hawaiian waters, ranging in size from the 8 in. pygmy shark to the up-to-50 ft. whale shark. There are eight species that are commonly sighted near shore, most of which pose little threat to humans. The tiger shark, recognizable by its blunt snout and the stripes on its sides, is the most dangerous species of shark found in Hawaiian waters and is known to attack humans. Though they will not seek out humans, tiger sharks usually reside near the shore and therefore do come into contact with humans. That said, shark attacks in Hawaii are actually quite rare—only two to three occur each year. Surfers and spear fishers are at greatest risk of attack, and swimmers are advised to stay out of the water at dawn and dusk, when sharks are most active. Never swim alone, avoid murky water, and get out of the ocean if you’re bleeding; blood can attract sharks. Experts also advise against wearing high-contrast clothing or shiny jewelry and to avoid excessive splashing.

For More Information. Consult All Stings Considered, by Susan Scott and Craig Thomas, M.D. (University of Hawaii Press; $25), and How to Stay Alive in the Woods , by Bradford Angier (Macmillan Press; $20).