10 Dangerous Animals in the Cook Islands

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Every trip to a foreign country requires preparation. Above all, you should be aware of possible dangers, including those coming from animals. Because a closer encounter can spoil your stay and even be life-threatening.

There are ten potentially dangerous animals in the Cook Islands – and the reason why:

  1. Tiger Mosquito. Transmits Dengue-Fever.
  2. Stonefish. Injects a potent venom.
  3. Lionfish. Stings venomously.
  4. Porcupinefish. It kills you if you eat it.
  5. Sharks. Be aware of Tiger- and Bull sharks.
  6. Toxic Reef Fish. It causes Ciguatera fish poisoning.
  7. Centipede. Bites with venomous fangs.
  8. Crown-of-Thorn Starfish. Spikes inject venom.
  9. Bluebottle. Injects a harmful toxin.
  10. Fire Coral. Burns, scratches, or cuts.

You’ll find all the details about them in the following, why they are a danger, precautions to be taken to be safe from them, symptoms when you’ve been hit, and what to do if one has harmed you. This info will help you to stay safe and enjoy a great time in the Cook Islands.

Get also your free Dangerous Animals infographic at the end of this article.

1. Tiger Mosquito – Transmits Dengue Fever

IslandAwe – Dengue Fever in the Cook Islands

About the Tiger Mosquito or Aedes Aegypti

Clearly number 1 on the list of dangerous animals in the Cook Islands, as it is responsible for severe tropical diseases.

This insect is known as the Tiger mosquito because of the brown and white stripes on its back and legs.

Only the female mosquito bites for blood to nourish her eggs. The mosquito primarily stings in the daytime but also after sunset.

More and more, it is spreading worldwide and does not occur only in the tropics.

The Hazard

In the Cook Islands, the Tiger mosquito spreads Dengue Fever and Chikungunya. It is around day and night and all year round, more common in the wet season from November to March. Heaps of mozzies populate the rainforest and swamp areas.

With just a couple of annual cases, Chikungunya is a minor problem in the Cook Islands. Thus, we are not looking in detail into it. If you’d like to get some more information, check the WHO-Website for Chikungunya.

But since a few years, there are annual Dengue Fever outbreaks on the Cook Islands, with two out of the four Dengue variants appearing, DENV-1 and DENV-2. Luckily, most cases focus on Rarotonga only, while all the other islands are primarily Dengue-free.

The illness occurs 4-10 days after an infectious bite, and the symptoms usually last 2-7 days. There is no effective vaccine against Dengue. If the sickness turns into severe Dengue fever with bleeding complications, it can be lethal. An estimated 400 million people are infected with dengue fever each year worldwide, and around 100 million develop the disease.

Here are more facts about Dengue fever, published by the WHO.

With several hundred Dengue cases per year in the Cook Islands, the Tiger mosquito ranks first on the list of dangerous animals in the Cook Islands.


Thus, as a precaution, avoid mosquito bites by doing the following:

  • Use mosquito nets and wear long light pants and shirts when possible. Don’t wear dark colors; they attract mosquitos. 
  • Use a strong insect repellent containing DEET. The insect repellent “OFF! Family care” is quite helpful and available on Raro as the Australian “Bushman” is. 
  • The mosquitos tend to breed in humid and stale water areas. Hence, avoid risk areas, such as swamps and rainforests.

To eradicate Tiger mosquito larvae, the Ministry of Health regularly sprays insecticides on Rarotonga.

Symptoms of Dengue Fever

  • High fever. Around 40 C/ 104 F, over several days.
  • Pain behind your eyes.
  • Muscle and joint pain.
  • Severe and itchy rash.
  • Stomach and bowel problems, Nausea & vomiting.
  • Loss of Appetite.
  • Fatigue.

Unfortunately, it also comes with some long-term side effects, for example, recurring fatigue, joint paint, and hair loss.

What to Do If You Have Dengue Fever

  • First of all, get a blood test to confirm an infection if you recognize the symptoms. You should know for sure whether you suffer from Dengue fever and which serotype it is.
  • Blood tests. Every three days, you should have your platelet count confirmed. It is one indicator of the severeness of the disease. The lower the number of platelets, the more your body is weakened.
  • Take only an appropriate pain reliever, not one which can aggravate the disease. Avoid Aspirin or Ibuprofen, which increase the risk of internal bleeding.
  • Stay hydrated. Because the fever dehydrates the body, and you don’t feel like drinking or eating at all. Get an infusion at the hospital or a doctor’s office if you cannot handle it yourself.
  • Rest and help your body to recover. 
  • Use local natural medicine made from papaya leaves (find the recipe in our special post about Dengue *) .
  • There is no further medical treatment available. Unless you suffer from severe dengue fever and you need intensive care.

* Pietro and I, we both became sick with Dengue in 2020. For a first-hand insight on this experience, have look at our particular post about Dengue, where we wrote down our daily experience throughout the disease.

2. Stonefish – The World’s Most Venomous Fish

IslandAwe - Stonefish

About the Stonefish

The Stonefish is the most venomous fish on earth and thus clearly one of the dangerous animals in the Cook Islands.

It is up to 40 centimeters/ 16 inches long, with crusty brown or grey skin, which makes it look like a stone. On its back, it carries 13 sharp, highly venomous spines.

The Hazard

The Stonefish is a master of camouflage, and you hardly recognize it next to a rock or hidden under the sand. So you can simply step on it. But it also occurs on land, like on the beach, and can harm you as the fish can go without water for 24 hours.

It injects a strong venom through the dorsal fin spines if you step on it. In some cases, it stung people on Rarotonga in the belly and buttocks while they were sitting or lying in the shallow water of the lagoon. 

A sting is excruciating and can be fatal, which puts it in second place of dangerous animals in the Cook Islands. Although Stonefish occur more often in the wet season (November-March), they are present around the year in the Cook Islands’ lagoons. Luckily, severe incidents are rare.


  • Wear sturdy closed reef shoes in the water that cover the soles of your feet.
  • If you walk in the water, keep a safe distance to rocks and coral banks.
  • Watch your step and where to sit or lie while being in the water.
  • Be cautious on the beach because a stonefish can occur outside the water.

Symptoms After a Sting

  • Excruciating pain at the site of the sting, which can spread quickly into the entire limb. 
  • Swelling
  • The skin around the sting turns into a lighter color because of an oxygen decrease.
  • Circulation problems, difficulty in breathing, up to heart failure can occur.
  • Confusion, numbness, and fainting are possible.

What to Do If Stung by a Stonefish

  • First of all: React – the sooner, the better.
  • Seek immediate medical treatment, call emergency. 
  • Treat the wound with hot water. As hot as you can bear, but maximum 45 C/ 114 F, to not damage the tissue even more. This helps to break down the toxin.
  • Get the antivenom as soon as possible to neutralize the inflammatory and lower the pain. 

3. Lionfish – A Threat to Humans and Nature

IslandAwe - Lionfish

About the Lionfish

It’s a beautiful maroon-colored fish with white stripes, fan-like fins, and floating tentacles.

But it also hosts 18 venomous spines, which are scattered around its body. In terms of size, a lionfish can reach up to 45 centimeters/ 18 inches.

The Hazard

The Lionfish is spreading rapidly across the oceans and is a significant threat to many ecosystems. It is a top predator which kills native plants and animals in a battle for limited food resources.

Also, the Lionfish injects venom through its spines if you touch it. A sting is very painful and requires immediate treatment. You can encounter Lionfish in the lagoon of Rarotonga and behind the reef. Its increasing occurrence and toxicity puts it in third place on the list of dangerous animals in the Cook Islands.

Precaution: Do not touch it.

Symptoms After a Sting

  • Severe pain at the site of the sting.
  • Swelling.
  • Abdominal pain, nausea, and vomiting are possible.
  • Allergic reactions can occur.
  • Fainting and heart rate problems may occur.

What to Do If Stung by a Lionfish

  • Carefully remove the spins without squeezing the venom glands. 
  • Clean the wound with soap and water first.
  • Treat the wound with hot water, as hot as possible. Do not exceed a maximum of 45 C/ 114 F not to damage the tissue further. This helps to dilute the toxin.
  • Seek medical treatment in severe pain, muscle cramps, and extreme cases with respiratory distress and paralysis.
  • There is no antivenom available.

4. Porcupinefish – The World’s Most Poisonous Fish

IslandAwe - Porcupinefish

About the Porcupinefish

It is the most poisonous fish on earth and a member of the pufferfish family.

The Porcupinefish can grow up to 30 centimeters/ 12 inches. Its skin is covered with black/ brown dots and spines.

When it feels threatened, it can inflate up to three times its original size, by swallowing water or air.

The Hazard

Another of the dangerous animals in the Cook Islands, because it’s deadly to humans and other fish if eaten. It carries a nerve toxin (Tetrodotoxin) that attacks the neurological system. This toxin is 1.200 times more poisonous than cyanide and can kill 30 humans.

Ironically, in Japan, the fish is a delicacy once the poison is removed correctly. This dish is called Fugu. What people like about eating this fish is the numbing effect that comes with it. Even though chefs are highly trained to do so, restaurant guests still die from it.

If eating an unprepared Porcupinefish, a person usually dies from 4 to 24 hours from the time of intoxication.

If you touch or step on a Porcupinefish, the sharp spikes can injure you. Since the toxin is also present on the fish skin, it can get into your bloodstream through an open wound. This fact also makes the animal venomous, not just poisonous.

Thus, a Porcupinefish is not venomous by injecting the toxin through its spines actively. But the toxin can get into the body accidentally through an injury.

The Porcupinefish is found everywhere in the Cook Islands, inside the lagoons and outside.


  • Do not eat Porcupinefish – under no circumstances.
  • Do not touch it with bare hands; wear gloves and avoid stepping on it.

Symptoms After Eating (Start About 30 Minutes Later)

  • Numbness of mouth and tongue, vomiting.
  • Rapid heartbeat, pulse, and respiration are slowing down.
  • Paralytic state, resulting in death.

What to Do If You Ate a Porcupinefish

Seek immediate emergency medical treatment. Artificial respiration may keep a person alive for even medical care at the hospital. There is no known antidote.

What to Do If You Touched or Stepped On a Porcupinefish

  • Wash your hands/ feet thoroughly. 
  • Seek immediate medical treatment if touching or stepping on it resulted in an open injury. 

5. Unpredictable Bull Sharks and Tiger Sharks

IslandAwe - Silhouette of Sharks

About the Sharks

Although fatal incidents with humans only occur in sporadic cases, sharks can act unpredictably and attack without being provoked. 

Some of the shark types are considered potentially dangerous for humans because of their aggressive nature and size.

The Hazard

The marine area of the Cook Islands hosts a variety of sharks. Around Rarotonga, you mostly come across the more relaxed Whitetip-, Blacktip-, and Grey reef sharks. And also a couple of Hammerhead sharks.

But be aware that there are also more aggressive species, like

  • Tiger sharks
  • Bull sharks
  • as well as Oceanic whitetip sharks

Besides, having a look at the entire Cook Islands, you can add the following shark types to the list, of which only the Nurse shark is considered harmless:  

  • Dusky Shark
  • Silky Shark
  • Silvertip Shark
  • Nurse Shark
  • Lemon Shark

Especially Penrhyn, the northernmost island, has an abundance of shark life. Hence, it has the nickname Shark Island. Marine scientists reckon that there are still unknown species. 


  • Keep your distance so that sharks do not feel threatened.
  • Do not get in a panic if sharks come close to check you out. Sudden movements can trigger an attack.

What to Do If You Have an Unpleasant Encounter

  • Get out of the water immediately, but calmly.
  • In case you got hurt, seek medical attention.

6. Toxic Reef Fish

IslandAwe - Toxic Reef fish

About the Ciguatoxin

In this case a toxin brings some fish to the list of dangerous animals in the Cook Islands.

The Ciguatoxin grows on and around corals; tiny marine organisms produce it. A couple of reef fish eat corals and with it the toxin, like Parrotfish and Triggerfish. And this is how the poison gets into the food chain. 

If you eat fish that is contaminated with the Ciguatoxin, you can get Ciguatera fish poisoning (CFP). It is a foodborne illness, the most frequent type of seafood poisoning. The Ciguatoxin is heat stable, and cooking doesn’t destroy it. You also do not smell or taste it. 

The symptoms of toxification start from 30 minutes up to 2 days, and it can take a few weeks to months to fully recover.

The Hazard

The Ciguatoxin is present in the lagoon of Rarotonga. In rare cases also behind the reef. And there are heaps of fish that potentially carry the toxin. People that (spear)fish in the lagoon to eat it are at risk for CFP. Hence, these toxic reef fish belong to the group of dangerous animals in the Cook Islands.


Do not eat any reef fish. Unless local people

  • confirm that the Ciguatoxin is not present at the moment or 
  • advise which fish is safe to eat.
  • Ideally, do not eat fish liver or fish head at all.

Symptoms of CFP

  • Abdominal pain, vomiting and diarrhea.
  • Numbness and itchiness of lips, tongue, hands and feet.
  • Skin rash.
  • Temperature reversal (hot feels cold and cold feels hot).
  • In severe cases, life-threatening heart and respiratory problems can occur in the first 24 hours.

What to Do In the Case of CFP

  • Ciguatera is not curable; the symptoms usually disappear after a few days. However, neurological problems may stay longer. 
  • Seek medical support for medication to reduce neural pain or relieve itching.
  • Stay hydrated, especially when you suffer from diarrhea and vomiting.
  • There is no antidote available.

7. Venomous Centipedes

IslandAwe - Centipede

About the Centipede

The Centipede is dark brown and up to 15 cm / 6 inch long, with 21 pairs of feet. The first pair has developed into venomous fangs. It bites if it feels provoked or threatened. 

While defending themselves, they sometimes roll up the back of their body like a scorpion. 

The Hazard 

A centipede injects venom with its head fangs. A bite is very painful.

On Rarotonga, there are heaps of centipedes. Its elongated dark body with scales and that many feet looks quite disgusting.

Although they prefer dark, earthy, and humid places, they often come into the house. And a surprising encounter usually ends with a harmful bite, which brings the centipede to the list of dangerous animals in the Cook Islands.


  • Do not touch or step on it. And watch the head with the venomous fangs. 
  • Close up gaps and openings to keep it out of the house.
  • To be honest: Kill a centipede if you see one. Cut it into pieces with a shovel or similar.

Interesting fact: On Rarotonga, chicken like to eat centipedes. They reduce their population considerably. With chicken around, you have less centipede problems. 

Symptoms of a Centipede Bite

  • Severe local pain.
  • Two puncture marks on the skin.
  • Redness and swelling immediately after the bite.
  • In case of a severe (allergic) reaction, intense swellings, itchiness, dizziness, nausea, chills, fever, and heart palpitation can occur.

What to Do If You Got Bit by a Centipede

  • Apply heat, hot water, or compresses. It dilutes the venom.
  • Disinfect the wound to avoid an infection.
  • Use an ice pack only to reduce the swelling after the first treatment.
  • To beat pain, allergic reaction, and inflammation, use pain pills and anti-allergic/ antihistamine ointments or tablets.
  • Check your tetanus vaccination and get one if it’s due.
  • Seek medical treatment in case of a severe reaction. Or if the symptoms do not weaken within 48 hours.

8. Stinging Crown-of-Thorns Starfish (COTS)

About the COTS

Like all starfish, it has a disk-like body with radial arms. Its color is purple-brow, and it reaches a size of up to 35 centimeters/ 14 inches. The countless sharp and venomous thorns-like spikes on the COTS’ body can grow up to 5 centimeters/ 2 inches.

The Hazard 

The spikes cut and sting painfully and venomous, if you touch or step on it. That secures the COT a place among the dangerous animals on the Cook Islands.

Over the last years, the COTS has become a problem on Rarotonga. In an outbreak, literally hundreds of them populate the reef area. They also come into the lagoon.

COTS are a threat to nature since they feed on corals and destroy them over time. The Cook Islands started a program to eradicate this starfish, in Maori called the taramea.

Precaution: Avoid direct contact with COTS, do not touch or step on it. Ideally, wear reef shoes and gloves. 

Symptoms After a Sting

  • Sharp stinging pain.
  • Persistent bleeding, caused by the toxin. 
  • Swelling.
  • Nausea.
  • If the thorns break and remain in the tissue, they cause continual pain. 

What to Do if Stung by a COT

  • Immerse the affected area in water as hot as possible, not exceeding 45C/ 114F, for 30-90 minutes. It dilutes the venom.
  • Pull out all spines in the wound with a tweezer. In case spines remain in the tissue, seek professional help to remove them completely.
  • Clean thoroughly with soap and water to avoid an infection.
  • Check your tetanus vaccination and refresh if it’s due.
  • Use hydrocortisone cream 2-3 times per day to reduce itchiness.
  • See a doctor if the pain persists or in case of an infection.

9. Terrifying Bluebottles

IslandAwe - Bluebottle

About the Bluebottle or Portuguese Man O War

Another unpleasant marine animal and part of the crowd of dangerous animals in the Cook Islands.

A bluebottle looks like a jellyfish, but it is a colony of small polyps living as a unit. While one polyp is responsible for moving (=floating), the others’ job is catching food, digesting, and reproducing.  

The floating body can reach about 15 centimeters / 6 inches, but the long blue tentacles grow up to 10 meters/ 33 feet. A bluebottle also hosts smaller invisible tentacles underneath its body.

All tentacles are venomous.

The Hazard

A sting is very painful, with continuous injection of its toxin until you remove every single tentacle. Thus, it is not only one of the dangerous animals in the Cook Islands but also in the oceans worldwide.

Since the majority of its body is transparent, you often see a bluebottle very late. Especially if the water is murky or troubled. Bluebottles still sting, even if dead or washed on the beach.

Bluebottles do not actively swim; they are drifting through the water. So, they might hit you because you are simply in their way. 

On Rarotonga, bluebottles are usually carried over the reef in stormy weather and end up in the lagoon. It does not happen too often, but you come across them.

Precaution:  Avoid any contact.

Symptoms of a Sting

  • Severe, burning pain.
  • A red line where the tentacles touched you.
  • Swelling, itchiness, also blister might develop.
  • Abdominal pain, headache, nausea, and vomiting are possible.

What to Do If You Got Stung by a Bluebottle

  • Remove all tentacles and stinging cells on your skin immediately. Do not use bare hands to avoid further stings! 
  • Treat the wound with hot water, tolerable to your skin but maximum 45C/ 114F, for at least 20 minutes. It will reduce the pain.
  • After the first treatment, and if it still hurts, you can apply ointment to reduce the inflammation or antihistamine creme.
  • Do NOT apply vinegar. It will increase the pain of a bluebottle sting. 
  • In severe cases where a sting causes a strong allergic reaction, difficulty breathing, or similar, seek medical help. 
  • Also, see a doctor if you got stung in sensitive areas, such as the mouth or eyes. 

10. Burning Fire Corals  

IslandAwe - Fire Corals

About the Fire Coral

Fire corals look like any hard corals, fan-like, branched, and come in different colors from green-yellow to dark orange.

In fact, they are not corals but a skeleton filled with polyps. Polyps also sit on their top ends, that sting when touched.

The Hazard 

In the lagoon and the outer reef of Rarotonga, various types of corals die and grow in recurring cycles. Fire corals are always present; you can recognize them by their bright yellow branches.

But if you touch or brush a Fire coral, it will cause a painful sting and a nasty rash. Cuts from the coral skeleton can intensify an injury and lead to an unpleasant infection. Thus, they have to be considered one of the dangerous animals in the Cook Islands.

Precaution: Keep a safe distance to fire corals. Do not touch or scrape against it.

Symptoms of a Sting

  • Painful burning or stinging experience at the area of contact.
  • Raised itchy rash that feels hot and can last up to two weeks.
  • In some cases, side effects can occur. Such as lymph gland swelling, nausea, vomiting or abdominal pain, and more.
  • An Allergic reaction is also possible.

What to Do After a Sting of a Fire Coral

  • Rinse the affected area with marine water because fresh water will increase the pain.
  • Treat with vinegar (5% acetic acid) or alcohol (70% isopropyl) to neutralize the toxin.
  • Remove all parts of the fire coral from the wound with a tweezer or tape.
  • Apply hydrocortisone cream 2-3 times per day to reduce itchiness and rash.
  • See a doctor if you start experiencing an allergic reaction, infection, shortness of breath, or swelling.

PS: Dangerous Animals in the Cook Islands – Spiders or Snakes?

Having read about these 10 dangerous animals in the Cook Islands, you might now also ask the question if there are snakes or spiders around?

In general, there are spiders all over the Cook Islands, but there are no snakes at all. However, none of the following wildlife is part of the group of dangerous animals in the Cook Islands.


Most of the spiders are rather small, invisible, and harmless, and not on the list of dangerous animals in the Cook Islands.

Rarely you encounter a Huntsman. This spider tends to terrify people only because of its size of up to 15 centimeters/ 6 inches and long hairy legs. But, they only bite if they feel threatened. In this case, an icepack usually relieves the pain.

More often, you come across the Jumping spider. Just about a centimeter/ half an inch long, it likes to hide in gaps in furniture, windows, and doors. If you get too close because you simply don’t see it, it might bite you. A bite results in numbness of the area or limb for about 30-60 minutes.

No Snakes but Eels

You might see several snake-like eel species, for example the banded, dotted, or crocodile snake eel. They look like snakes, but in fact, they are fish with the characteristic dorsal fin. These creatures are not one of the dangerous animals in the Cook Islands.

However, be aware of the Giant moray eels since they defend themselves in case of a threat. So do not come too close and be safe from their harmful teeth.

Click the image below to download your free 10 Dangerous Animal of the Cook islands PDF Infographic

10 Dangerous Animals in the Cook Islands
Dangerous animals of Cook Island Infographic.

You Might Also Be Interested In …

We hope this post gives you a good idea of dangerous animals in the Cook Islands, the wildlife to be aware of and stay away from during your time in the Cook Islands.

If you are interested in more facts about the Cook Islands’ wildlife, have a look at these related topics:

What Do I Need to Know About Animals in the Cook Islands in General?
Have a look at the 9 Important Facts about Animals in the Cook Islands.

Which Marine Animals Can I Find in the Cook Islands
Here are all the details about the Vibrant Marine Life in the Cook Islands

Are There Any Sharks in Rarotonga?
We’ll give you an insight into where in Rarotonga you find which types of sharks.

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