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Thailand: Dangerous Animals

Will has lived in Thailand for several years and is aware of the many dangers that beset unwary visitors.

Most dangerous insects and animals in Thailand.

Most dangerous insects and animals in Thailand.

Dangerous Animals in Thailand

Let's face it, it's always a good idea to be prepared for the bad things that might happen health and safety-wise.

The creatures described below certainly shouldn't discourage you from visiting one of the world's great holiday destinations, Thailand. The sun, coral seas, welcoming people, spectacular landscapes and fantastic food more than compensate for the small risk of encountering something nasty.

Dangerous Animals on This Page

  • Poisonous Snakes
  • Giant Centipedes
  • Jellyfish
  • Coral
  • Mosquitoes
  • Scorpions
  • Spiders
  • Ants
  • Lion Fish
  • Poisonous Caterpillars
  • Dogs
  • Monkeys
  • Leeches
King Cobra. Snakes are common in Thailand, be wary of any grassed areas or undergrowth

King Cobra. Snakes are common in Thailand, be wary of any grassed areas or undergrowth


In Thailand, these are always scary and often dangerous.

If there is grass or undergrowth, there is a chance there are snakes, even in city parks or hotel gardens. The good news is most will run (or slither) away if they see you coming. The bad news comes if you stand on one. Beating the grass with a stick might look silly, but if you have to cross open country it’s not a bad idea for your personal safety.

Kraits are especially to be avoided!

Kraits are especially to be avoided!

Spitting Cobras are capable of spraying venom into a person's eyes from three meters, so if you see a snake, give it a wide berth. Trying to kill a snake is an especially dangerous activity. The genuinely dangerous varieties, especially cobras and pit vipers, will not try to escape, they will attack.

If the worst comes to the worst and you are bitten, don’t worry about identifying the snake, go straight to a hospital. Thailand has an excellent health system that is well used to snake bites. If you receive care within an hour or two you should be fine. Roughly 7000 snake bites occur every year (rather less than occur in the US) but there are only thirty or so deaths. In Thailand, travel insurance is recommended since treatment can be costly- around 200 dollars a night, depending on location.

First Aid for Venomous Snake Bites

First aid for snake bites involves washing the wound with soap and water, immobilizing the bitten area and keeping the wound lower than the heart. If a hospital is more than half an hour away a bandage can be used a few inches above the wound to reduce the spread of venom. The bandage should be loose enough to work a finger beneath or restriction of blood flow can cause injury.

Scolopendra. Can grow to the size of a man's forearm.

Scolopendra. Can grow to the size of a man's forearm.

Giant Centipedes

Giant centipedes are found all over Thailand, in urban areas as well as forests and can grow to the size of a man's forearm. Like a lot of insects in the tropics, if it rains heavily, giant centipedes like to come indoors to avoid drowning. A shoe or bag can provide a handy place for the creatures to hide, and if they are surprised and can't escape they will bite.

Their bite does not kill but for three or four days the victim will be in serious pain- even a shot of morphine from the local hospital will only take the edge off.

The bite marks are similar to those of a small snake and centipede bites can be mistaken for snake bites in the dark. The victim requires anti-tetanus, painkillers and rest. In the case of an allergic reaction, breathing support may be necessary,

They are plenty big enough to notice during the day, but for your own safety never walk around without shoes in the dark, even indoors!

Jellyfish can be a menace after storms.

Jellyfish can be a menace after storms.


Sharks are not a problem in Thai waters, so jellyfish are the most dangerous animal you are likely to encounter while swimming. They can cause a lot of pain and leave injuries that take weeks to heal. In extreme cases, ugly scars remain.

Avoid swimming during overcast periods or after storms. Strong sun is dangerous to jellyfish and they won’t come close to shore in good weather. If stung, carefully remove any jelly from the skin and bathe with vinegar if available. Freshwater will make the pain worse. If stings cover a large area of your body or the pain is severe, a trip to the hospital is worthwhile. A single fatality was reported recently in Phuket.


Dead coral can be razor sharp and cause nasty cuts. Living coral can cause stings similar to jellyfish. Divers and snorkelers should be aware.

Mosquito feeding on a human arm.

Mosquito feeding on a human arm.


Mosquitoes can be a serious threat to health in Thailand, transmitting Malaria, Dengue Fever or Japanese Encephalitis, but even if these dire diseases did not exist, these insects can spoil a holiday purely by their irritation factor.

Mosquitoes avoid sunlight and are mostly a problem at night. Even so, during daylight hours they can be about their business in shady places- under trees, under restaurant tables and in poorly lit interiors. Covering up at night with long sleeves and trousers is a good option but be aware that the larger varieties can pierce cotton to reach a meal.

Most bites will only cause minor irritation but If you are allergic to them, the reaction can lead to large maddening swellings that take days to subside.

Most local pharmacies have English speakers who can recommend a range of preparations to reduce the annoyance. ‘Tiger Balm' ointment contains a natural anesthetic and is a favorite with Thais. 'Clobet cream' is a widely available anti-inflammatory, anti-bacterial, cortisone cream.

Whilst modern buildings are generally well screened from mosquitoes, picturesque beach cottages made from bamboo often are not. If a mosquito net is provided for sleeping, it really is a good idea to use it. Outdoors, insect repellents based on DEET offer genuinely effective protection. The first evening that you forget, you will realize just how effective!

Thailand Scorpions

These can be the size of your hand and they are surprisingly quick. Strangely, the smaller they are the more painful the sting since the poison in their bulbous tails is usually more concentrated. The legend is they are attracted by the smell of stale beer, so get rid of empty bottles swiftly.

Black Scorpions, the most common variety in Thailand, very rarely deliver a fatal sting and aren't thought of as a serious health risk. In fact, compared to their lethal cousins in Mexico and the Middle East, the sting is said to be mild.

Prompt hospital treatment is recommended, however, as some people suffer severe allergic reactions. In a recent case, a Welsh man died in his home country many weeks after being stung in Thailand.

Treatment consists of anti-venom administration, support for breathing if necessary, antibiotics and anti-tetanus injections. The application of ice packs can reduce pain.

Tarantulas live mainly in underground burrows in forests.

Tarantulas live mainly in underground burrows in forests.


Thailand has plenty of big scary-looking spiders, but only a few species will bite a human being. This still means thousands of bites every year.

Luckily, deaths from spider bites are very rare- less than 3 per year across the whole world and these are generally a result of allergic reactions.

The most dangerous spiders in Thailand are mainly forest dwellers. Some Tarantula species have a reputation for aggression and the bites are painful and best treated in hospitals with anti-venom. Symptoms can include swelling, exhaustion, muscle cramping, difficulty breathing and fever. Sometimes, these occur days after the bite.

For your safety, empty out your shoes and shake your clothes before wearing them, especially in rural areas!

Even the smallest ants have ways to make you suffer.

Even the smallest ants have ways to make you suffer.


There are more species of ants in Thailand than anyone has had the time to count. They do not run away if they chance on you. They attack! The larger varieties usually rely on brute strength to vanquish their insect enemies. These will only give you a nip with their powerful jaws. The smaller ones- and some are so small they are barely visible- have all sorts of poisons and allergens to inject into your skin. After a day or so, the worst bites can feel as if someone is slowly driving a spear through your body. Watch out for ants at all times!

The best defense is hygiene: any food residues in a house or hotel will quickly attract columns of ants, as will food stains on clothes. Cortisone creams will reduce inflammation and pain effectively if you are bitten. Local remedies like Tiger Balm are less effective.

Caterpillars of this kind can eject a cloud of poisonous hairs which will drive you crazy on contact.

Caterpillars of this kind can eject a cloud of poisonous hairs which will drive you crazy on contact.

Poisonous Caterpillars

Brightly colored insects are often poisonous. Bright colours advertise danger and discourage other animals from attacking, and caterpillars are no exception. The creatures pictured have poisonous hairs which they can eject into the air. Any that land on your skin will drive you crazy. Some species are reputed to be capable of killing a small dog. Thai people call them Buung Haan.

Lion Fish. Photo: Christian Mehlführer

Lion Fish. Photo: Christian Mehlführer

Lion Fish

Lion Fish are one of the most venomous fish in the open sea. The spines are actively used to inject toxins into any living thing that approaches too closely. In human beings, the result is acute pain with the possibility of breathing problems and vomiting. Hospital treatment is strongly recommended although the poison is almost never lethal.

It is very rarely found near sandy beaches so is not dangerous to swimmers. Divers and snorkelers should be aware of the safety issue.


Dogs are a big part of life in Thailand. People keep increasing numbers as pets. There is also a massive stray population which can have significant health implications.

In towns, many dogs wander free, often sleeping on major roads whilst the traffic carefully winds around them. Eradication programs are out of the question because of the Buddhist respect for life. Sterilization programs have proved ineffective.

Stray dogs in Thailand are generally docile but they can be intimidating in large packs at night and some will bite if they feel threatened.

One of the best ways of dealing with aggressive dogs is to back away whilst maintaining eye contact and being willing to defend yourself. Thais will not hesitate to use a stick or stone in self-defense, and neither should you.

If you are bitten, it is essential to get treatment immediately because of the widespread problem of rabies in Thailand. Again, travel insurance is highly recommended.


Genuinely wild monkeys are wary of human beings and won't approach people too closely. In some tourist locations, however, and around certain temples where they are tolerated, many monkeys have lost their natural fear and beg for food. They are cute when they are getting what they want but can sometimes be a menace, especially in large numbers.

Like monkeys anywhere, these creatures will steal anything, especially if it is edible. They can unzip bags and tear through the contents. They can rip mirrors from cars and motorcycles. They may even try to bully you out of a snack. This can be scary for children and sometimes a threat to their safety. Stand up to them (use sticks and stones if you have to) and they back off.

If you are bitten go to a hospital immediately as there is a risk of rabies.


Leeches are common amongst wet vegetation and in still waters.

In water, they actively swim towards any disturbance.

On land, if they detect the presence of a human being or an animal they stand up and wave from side to side in a searching motion. If they find contact with skin, they quickly attach themselves with their lower sucker, and the head probes the skin for a good place to penetrate.

Minute, razor-sharp teeth slice an opening and the head enters. They gorge themselves on up to seven times their own body weight in blood before dropping off.

An anticoagulant is used to keep the blood flowing during feeding and the wound may bleed for several hours afterwards.

Leeches pose the greatest threat to health in Thailand during flooding in towns and cities. The floodwater brings sewage to the surface from drains. Leeches swept in from country areas cause wounds which become infected. During a series of recent floods across Thailand, many thousands of people became ill in this way. The government recommended wearing jeans and tying plastic bags around the feet to keep the leeches at bay- a low-tech solution that would probably help.