Borneo is the third largest island in the world, located in Southeast Asia. Around half of the island is covered in rainforest, but it contains many other habitats too – including mangrove swamps, farmland, urban areas, and beaches.
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In this list of Borneo’s ten deadliest animals, we venture from the depths of the rainforest to the shallow oceanic waters of Borneo’s coastline, visiting swamps, rivers, and beaches along the way.
10 deadliest animals in Borneo
Bornean bearded pig (babi hutan) (Sus barbatus)
Standing at three feet tall and weighing 100-300lbs, these wild pigs roams Borneo’s rainforests. Their diet consists of fruits, seeds, insects, eggs and carrion. While not naturally aggressive, if cornered they can become extremely dangerous, especially if there are young around.
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Using their 10-inch-long tusks, these pigs have been known to kill young orangutans. Not to eat, but over competition for food.
If these pigs are able to take down orangutans, then it’s highly likely they can take down a human. Best not surprise one in the forest... and best not attempt to steal one’s dinner, either.
Bornean sun bear (beruang madu) (Helarctos malayanus euryspilus)
The smallest bear in the world, Bornean sun bears are just less than 30 inches tall and can weigh up to 150 pounds. But don’t let this fool you: despite their small stature, they are not an animal you’d want to bump into in the forest.
Bornean sun bears are elusive animals that are endemic to Borneo, meaning they are not found anywhere else in the world. They live in dense rainforest and spend most of their time up trees. Their diet consists of nuts, berries, insects, honey and small mammals.
To help them forage effectively, sun bears have evolved long claws for digging up insects, powerful jaws for biting through bark (hoping to reach tasty insects within), and the largest canines of any bear, relative to body size. This constellation of traits makes them a fearsome enemy if they choose to attack, which they often do when surprised.
Locals living in the Bornean rainforest avoid walking in sun bear territory because of the risk of surprising a bear. Sun bears are very difficult to get away from, as they become very aggressive and often engage in a prolonged attack.
While it’s unknown how many bear attacks there have been, the fact that local populations avoid this animal is a sure sign that they are not to be messed with!
Bornean pygmy elephant (gajah kalimantan) (Elephas maximus borneensis)
A subspecies of the Asian elephant, this is the smallest elephant in the world. But much like the sun bear, its relatively small stature does not mean it isn’t dangerous.
Standing at eight-foot-tall, weighing several tons, and – if male – sporting two tusks that can each reach five feet in length, Bornean pygmy elephants live in small family groups in the rainforest. Humans who venture too close to lone males or herds (especially when calves are present) have been charged at and, occasionally, gored to death. Death occurs through a combination of trampling and tusk wounds.
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Sadly, there are only about 1500 Bornean pygmy elephants left in the wild. They are critically endangered because their habitat is being destroyed, mainly due to logging and the development of palm oil plantations.
Lesser banded hornet (tabuan) (Vespa affinis)
Lesser banded hornets live in sociable hives. They build these hives high in trees or in thick undergrowth. If they think their hive is under threat, individuals release alarm pheromones that encourages the whole hive to attack.
Hundreds of hornets may sting a person in these mass attacks, and such swarms often cause anaphylactic shock and organ failure, which may both lead to death.
While many species of hornet engage in such behaviour, the lesser banded hornet – which is docile if undisturbed – is particularly notorious for its aggression and sustained attack on those it perceives as a threat. Every year, multiple people die in Southeast Asia because of this species.
King cobra (ular raja kobra) (Ophiophagus hannah)
King cobras are not a snake to be messed with. Native to Borneo’s rainforests and wetlands, they can grow to over sixteen-foot-long and have venom so potent that one bite could, theoretically, kill 20 people. The venom is neurotoxic, meaning that it acts on the nervous system to cause paralysis. This leads to suffocation as the bite victim cannot breathe.
While king cobra venom is extremely deadly, this snake does not often bite humans. They are reclusive and avoid people if possible. But, as with so many of Borneo’s wild animals, if they are disturbed or surprised then they may attack in self-defence. This is especially true if mothers are disturbed while guarding their nests (they are the only snakes to build nests, and are very defensive of them!).
Saltwater crocodile (buaya muara) (Crocodylus porosus)
Saltwater crocs can grow up to 20-foot-long and weight up to 2,200 pounds. In Borneo, they lurk in mangrove swamps, rainforest rivers and estuaries. Rather than actively hunting, crocs stay very still and wait for their prey to come close enough to be ambushed.
Due to the sheer power of their jaws, once a croc has something in its grip, there is almost no chance of escape. The prey will be dragged underwater and drowned.
Saltwater crocodiles aren’t fussy about their meals. They will target whatever comes close enough to eat – including humans. Globally, more than 100 humans a year die due to saltwater croc attacks.
Yellow-lipped sea krait (ular laut belang) (Laticauda colubrina)
This black-and-blue striped beauty is found on the Bornean coast – both in the sea and on beaches. Generally curious and friendly, this sea krait has been known to inspect divers before swimming away, and they are rarely aggressive towards humans. Except, that is, if they are stepped on by beachgoers or handled by fishermen who accidentally catch them in their nets. Then, in self-defence, they will bite.
Their venom is potent and immediately impacts the nervous system. While the bite itself is painless, the venom leads to a very painful death: fitting and paralysis followed by cardiac failure.
Luckily, these creatures don’t always inject venom when they bite. Because venom is so energetically costly to produce, they’d rather use it on catching prey than on scaring off a human. So, they will sometimes give a defensive ‘dry bite’ in the hope that this will make a human back off.
Reticulated python (sanca kembang) (Python reticulatus)
Reticulated pythons, who regularly grow to over 20 feet long, inhabit a range of habitats in Borneo, including rainforests, mangrove swamps and farmland. They are excellent swimmers and can also climb up trees, meaning they can be found on the ground, in water, and even in the rainforest canopy.
Most snakes do not eat humans, but reticulated pythons are an exception. They actively prey on humans. Indeed, an anthropologist based in the Philippines reported that one in four tribesmen had been attacked by the snake. In Indonesia, a woman was recently eaten by a reticulated python while she was tending her vegetable garden.
The way reticulated pythons kill is not pretty. As with all pythons, they are not venomous but kill their prey by wrapping themselves around their victim’s body and tightening their grip as the victim exhales. This squeezing motion causes the victim to have a heart attack.
Box jellyfish (ubur-ubur kotak) (Chironex fleckeri)
Found off the Bornean coast, the box jellyfish is the most lethal species of jellyfish on the planet. It was first identified by Dr. Hugo Flecker, who was keen to find out why so many swimmers kept mysteriously dying off the coast of Australia – where the box jellyfish also lives.
If any of its ten-foot-long tentacles touch a swimmer, microscopic darts fire out of cnidocytes (a type of cell that covers the tentacles in its millions) and these darts deliver a dose of powerful venom.
A small sting is excruciatingly painful but survivable. A stinging event that covers a large area of a person’s body is, however, harder to survive. Often, if treatment is not given, death by cardiac arrest occurs between three to five minutes after being stung.
Blue-ringed octopus (gurita cincin biru) (Hapalochlaena)
Living off the coast of Borneo, blue-ringed octopuses are tiny, beautiful, and extremely deadly.
Under 20 centimetres long, and living off a diet of small crabs and fish, they may seem innocuous enough, but one little octopus has enough venom to kill twenty adult humans. When they bite with their small parrot-like beaks, it barely hurts at all, and yet their venom will kill within minutes.
Symptoms of a bite include tingling, difficult breathing and paralysis, with death soon after. There is currently no antivenom available, and in remote regions there is a high risk of death because no medical intervention – such as mechanical ventilation – can be applied quickly enough.
With little chance of survival following a bite, this beautiful and deadly little octopus earns top spot.
Top image credit: Tropical Borneo/Getty Images
