The 9 Most Dangerous Animals in Hawaii

dangerous animals hawaii
Photo by Marc Schulte on Unsplash
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Hawaii is a collection of islands famous for its golden beaches, tropical climate, and unbeatable surf. The state comprises 137 volcanic islands set in the Pacific Ocean, about 2,000 miles from the US mainland. Due to their isolated position, many endemic forms of wildlife have evolved on the Hawaiin islands. While much of the state’s rich and varied wildlife is harmless, there are a fair few dangerous animals in Hawaii. 

From the hoary bat to the Hawaiin monk seal, and the state’s official bird, the Nene goose, Hawaii is famous for its abundance of native species, found nowhere else in the world. The majority of these fascinating species pose no threat at all to humans. But that isn’t to say that visitors to Hawaii are in for a totally risk-free time. Many of the most dangerous animals in Hawaii lurk off the state’s shores. 

So, what are these dangerous species, and how can we avoid them? Read on for a breakdown of the 9 most dangerous animals in Hawaii.

Box Jellyfish

Photo by Jeffrey Hamilton on Unsplash

The first animal on our list of dangerous animals in Hawaii is one of the most deadly: The box Jellyfish. These potentially lethal marine animals live in the Southern Hemisphere’s Pacific Ocean. Also known as sea wasps and marine stingers, box jellyfish are recognizable for their cube-shaped bodies.

Growing up to 10ft in length, each box jellyfish’s tentacles are covered with around 5,000 barbed stinging cells, called nematocytes. These help the creatures feed off a diet of shrimp and small fish, but the box jellyfish’s venom is also incredibly dangerous to humans. With toxins that attack the heart, nervous system and skin cells, box jellyfish venom can cause humans to go into shock and drown, or die of heart failure before accessing help. Those that do survive experience excruciating pain for a number of weeks, and are left with some pretty gnarly scars.

Interestingly, unlike most jellyfish that drift on the tide, the box jellyfish is an intentional swimmer. This, and their translucent bodies, can make them more difficult to avoid in the water. Perhaps unsurprisingly, lifeguards in Hawaii are very vigilant when it comes to jellyfish. If any are seen close to the shore, it’s quite common that beaches will be closed. If you are unfortunate enough to be stung by one of these jellyfish, experts recommend covering the area with vinegar, carefully plucking out tentacles one by one, and applying a heat pad.

Long-spined venomous sea urchins

With long, venomous spines, you don't want to step on a sea urchin
Rigel on Unsplash

The next on our list of the most dangerous animals in Hawaii also comes from the ocean. Long-spined venomous sea urchins – locally known as wana – lurk in the depths of the Pacific surrounding Hawaii’s shores. While small and static, these spined creatures pack of nasty punch. 

Sea urchins attach to coral, rocks, and other submerged surfaces in some of the state’s most popular surfing spots. Unfortunately, this makes stepping on them a fairly common occurrence. In fact, ending up with a sea urchin spine in one’s foot is somewhat of a rite of passage among the state’s die-hard surfing community. While by no means deadly, it’s certainly not a pleasant experience. The venom delivered from urchin’s spines can be very painful, and spines that break off and lodge in the body can be impossible to remove, though they dissolve eventually. 

In order to avoid having a nasty encounter with a sea urchin, travelers should remember to wear sea shoes where possible. And even when wearing shoes, it’s important to remain vigilant and avoid treading on rocks and coral. If you do end up speared by an urchin’s spine, there are plenty of medical professionals in Hawaii well-equipped to offer help. Soaking the wound in warm water and vinegar helps to break down the venom. Sea urchin wounds can become easily infected, so keep a close eye on the area.

Cone snails

Extremely venomous cone snails are among some of the most dangerous animals in Hawaii
Joe Belanger on Envato

There are 34 species of cone snails in Hawaii. With pretty, intricately patterned shells, it can be tempting to collect cone snail shells for souvenirs but be warned! They may seem harmless and unassuming creatures, but cone snails are some of the most dangerous animals in Hawaii. This is because of their venom, which can be deadly to humans. Hawaiin natives nickname cone snails ‘dizzy shells.’ This is because their venom can induce anaphylactic shock in humans. 

As we mentioned before, there are a fair few different species of cone snail in Hawaii, and luckily, not all of them are dangerous. In fact, many have venom that is no more powerful than a bee’s sting. But the toxins within the venom of three particular varieties – the Textile, Striated, and Banded Marble cone snails- are powerful enough to kill 10 people. Unless you’re an expert, it’s hard to tell one species of cone snail from another. So our advice would be to keep a wide berth of all snail-looking creatures and don’t go shell picking unless you’re with someone who truly knows their stuff!

Tiger shark

Tiger sharks are one of the most dangerous species of shark found in Hawaii
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From tiny sea critters to marine beasts, the Pacific ocean is home to many dangerous animals, but few are more feared than sharks. The tiger shark is one of the most dangerous sharks that live in Hawaii’s waters. Growing up to 13 feet in length, tiger sharks have blunt snouts and tiger-like stripes on their torsos. They are powerful predators, with an excellent sense of sight and smell. Tiger sharks are second only to great whites in attacking people, and due to having a very undiscerning palate, don’t tend to swim away after biting a human – earning them a fearsome reputation as man-eaters.

However, while films like Jaws have certainly given sharks a bad reputation, they don’t actually pose a great deal of threat to humans. This is particularly the case in Hawaii, where there are 2-3 shark attacks a year, and very few are fatal. Since records began in 1828, there have only been 11 shark fatalities recorded, mostly around the island of Maui. That’s a pretty low number if you consider the great deal of time that locals and tourists spend in Hawaii’s waters. Nonetheless, it’s important to remember that when bathing in the Pacific, you’re entering the shark’s world. Following basic safety tips, using common sense, and listening to the lifeguard’s direction is essential in ensuring you don’t endanger yourself, or the sharks.

Great white shark

While rare, great white sharks are among the most dangerous animals in Hawaii
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While far less common than tiger sharks, great whites have been seen off Hawaii’s shores. These legendary animals are the largest predatory fish on Earth – and definitely the most fearsome. They grow to an average of 15 feet in length, though some exceed 20 feet and weigh up to 5,000 pounds. With up to 300, razor-sharp teeth, and a keen sense of smell, great whites eat a varied diet of other sharks, crustaceans, sea birds, sea lions, seals, and small toothed whales like orcas. 

Great whites are responsible for between a third and half of all annual shark attacks worldwide, but the majority of these are not fatal. Great whites tend to ‘sample bite’ humans. In order words, they give them a little taste to see if they’re worth eating. After realizing they don’t like the taste of humans, they tend to swim away. Fatal attacks tend to happen when the sharks mistake swimmers and surfers for seals. Thankfully, great whites very rare in Hawaii so pose less threat in this part of the world.  

Moray eel

Moray eels have a nasty bite
Wouter Naert on Unsplash

Moray eels are one of the most dangerous animals in Hawaii. The state’s waters are crawling with them: there are over 80 species of moray eel, which can be found in holes and beneath rocks along the sea bed. These slithering critters reach up to 13 feet in length, have two sets of very sharp teeth and bulging eyes. They make for a pretty gruesome sight.

In 2018, a moray eel attacked a woman on Kuhio Beach in Waikiki, Hawaii. The wound was so painful that some thought she had been attacked by a shark. However, while moray eels can certainly exhibit aggressive behavior towards humans, these types of attacks are surprisingly rare. Eels tend to stick to themselves and are most active at night rather than during typical swimming hours. In order to avoid them, don’t enter the ocean at night (you shouldn’t be doing that at the best of times anyway!). Remember that these critters are extremely aggressive when someone invades their space, so keep well away if you do come across one.

Yellow-bellied sea snake

Yellow-bellied sea snake
Photo by Alex Figueroa on Flickr

Snakes are fairly rare on land in Hawaii, but its waters are home to a fairly venomous variety of snake: the yellow-bellied sea snake. As their name suggests, these snakes are recognizable due to their bright yellow underbellies. They have a brown upper body and can reach up to 35-inches in length. While they can stay underwater for up to 3 hours, they are sometimes seen in large groups of thousands, drifting on the surface and using the currents to wait for prey. 

Yellow-bellied sea snakes have a highly potent neurotoxic venom that is harmful to humans. However, fortunately, they tend to be timid creatures that avoid contact. There are no records of fatalities from yellow-bellied sea snakes in Hawaii.

Brown violin spider

The brown recluse spider is one of the only species of venomous spider in Hawaii
Timothy Dykes on Unsplash

Not all dangerous animals in Hawaii live in the sea. There are a number of spine-tingling creepy crawlies that you’ll want to keep a wide berth of. The brown violin spider is one of them. With long spindly legs and violin-style markings on their back, it’s hard to miss brown violin spiders. While not typically aggressive, the brown violin spider has a reputation for biting in self-defense. They pack a nasty bite, which can cause vomiting, dizziness, and severe pain. 

Largely nocturnal creatures, brown violin spiders like to hang out in isolated spots: think under woodpiles and in sheds. It’s for this reason that these arachnids are known as recluse spiders in the US. Take extra care around dark, dank spaces if you want to avoid what could be an unfortunate encounter.

Brown tree snake

The brown tree snake was probably introduced to Hawaii from Guam
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Hawaii has no native snakes, and the state takes great measures to remain this way. It’s illegal to own a snake, for example, and border officials rigorously check imports to ensure that the state remains snake-free. Unfortunately, a species of snake has slipped through the net. These are brown tree snakes. Originating from Guam, brown tree snakes are an incredibly invasive species that pose a great risk to Hawaii’s birdlife. They have brown bodies, large heads, and protruding eyes. Brown tree snakes are mildly venomous and can exhibit very aggressive behavior towards humans. While their venom is not fatal to adult humans, it can be to children

Brown tree snakes are still pretty rare in Hawaii. The authorities have been taking steps to try and cull the population of brown tree snakes before it grows too big and endangers the state’s fragile ecosystem. In 2018, for instance, the Hawaii Department of Agriculture imported four of the snakes in order to train sniffer dogs to hunt for the species. 

What is the most dangerous animal in Hawaii?

The most dangerous animal in Hawaii is the box jellyfish. These invertebrate predators have some of the strongest venom around. In humans, box jellyfish stings can lead to cardiovascular collapse and death as quickly as within 2 to 5 minutes. In fact, the 43 known species of box jellyfish cause more death and serious injuries than sharks, sea snakes, and stingrays combined. Luckily, however, the box jellyfish species found in Hawaii are not the most deadly of varieties. Still, it’s worth keeping an eye out for these cube-shaped creatures when swimming in Hawaiin waters. Their sting can be excruciatingly painful and leave skin permanently scarred.

Are there crocodiles in Hawaii?

There are no native crocodiles in Hawaii. The only place you’ll find these animals in Hawaii is in the zoo!

Are there poisonous spiders in Hawaii?

There are four native species of poisonous spider in Hawaii: the brown violin spider, the brown widow, the western black widow, and the southern black widow. The brown violin spider – aka the brown recluse spider – has long spindly legs and violin-style markings on its back. True to their name, these poisonous spiders like to keep away from human contact and hang out in isolated spots. However, they will bite if you come too close and are capable of administering a nasty venom that can cause severe pain.

Both western and southern black widow spiders have black bodies with red markings at the bottom side of their abdomen, but the southern species have an additional red dot on the abdomen. In general, male black widows are harmless – it’s the females you want to look out for. You can tell the sexes apart by size: the females tend to be much larger than the males, growing to half an inch long and up to an inch wide. Both varieties of black widows like to keep away from human contact in warm, dark, and isolated locations, such as garages and sheds. They will attack if someone disturbs their home, carrying a venomous bite that can cause cramping, nausea, hypertension, and pain.

The brown widow spider is less striking in appearance than its black and red cousins. It has a brown body with black markings. The brown widow makes its home in sheltered sites within vegetation and residential areas. While its bite is painful, it isn’t fatal. 

Fortunately, Hawaii’s native spider populations don’t tend to hang out in tourist areas. They prefer the residential areas and woodland to the beach, meaning that there’s little chance you’ll come across one unless you go poking in dark, damp, and isolated areas. All in all, poisonous spiders pose little threat to humans in Hawaii, so there’s no reason for arachnophobes to fear.

Are there deadly snakes in Hawaii?

Hawaii has no native species of snake – deadly or otherwise. This is partly owing to its isolated geographic position, and partly due to comprehensive efforts from local authorities to ensure that the state remains a snake-free zone. In fact, it’s a felony to possess or transport snakes in Hawaii, with violators risking a $200,000 fine and up to three years in prison. However, in spite of these best efforts, a couple of invasive species of snake have shown up in Hawaii in recent years. 

The mildly venomous brown tree snake, for example, has shown up on Hawaiin shores – but it poses more threat to the state’s birdlife than humans. Though rare, the yellow-bellied sea snake also populates Hawaiin waters. They carry a highly potent neurotoxic venom that is harmful to humans.

Finally, there’s the Brahminy blind snake – aka the Flowerpot Snake. Measuring at just 10 cm, this is the world’s smallest species of snake. Due to their size and their tendency to burrow into the soil, people frequently mistake these tiny, harmless critters for earthworms. Perhaps unsurprisingly, they pose no threat to humans – you could even say they’re kind of cute!

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Charlotte Hanwell is a writer and travel enthusiast from London. Her studies of Spanish language and literature have taken her from Barcelona to Buenos Aires. In between travels, she loves to run, read and cook her way around the world.