From the towering mountains of the Andes to the vast forests and wetlands of the Amazon basin, South America has some of the most ecologically rich habitats on Earth.
Despite enormous pressure from deforestation for mining, faming and timber, there is still – just – space for some extraordinary wildlife. And while there are myriad beautiful bird species, extraordinary mammals and countless invertebrates – many still to be discovered by humans – there are also many creatures that can be dangerous.
Many animals have fearsome jaws, claws and fangs for hunting prey, or toxins for defending themselves from attackers. But few actively hunt humans and most are far more afraid of us that we are of them.
Sometimes. however, humans do come into deadly contact with wild animals. Most of these conflicts occur when people enter the creatures' home ranges, destroying their habitats and putting pressure on populations. It is then that problems arise.
Here are 10 animals to admire – and to be wary of – in the wilds of South America.
10 deadliest animals in south America
Fer de lance snake – common lancehead
Fer de lance means 'spearhead' in French but it is a name that has stuck for this extremely venomous 1.5m species of pit viper found in the tropical lowlands of Central and South America. It is also found on the island of Trinidad.
Also know as the the common lancehead, it gets its names from the handsome triangular 'spearhead' patterning along its body. But it probably has a lot of other ruder names locally as it is regularly encountered on farms, especially banana plantations, where it hunts small mammals but also frequently bites workers. The fer de lance may account for 50 per cent of all snake bites in the region although it is not know how many people die from bites each year.
The venom from a bite prevents the blood from coagulating and can leads to uncontrolled bleeding . As well as loss of blood and swelling around the wound, victims can suffer kidney failure, blistering and necrosis where body tissues die rapidly. Symptoms include headaches, nausea, diarrhea. Bites from young snakes are more virulent and so more likely to be fatal.
Black caiman
Reaching almost six metres long and weighing up to 600kg, this largest member of the alligator family is the top predator in South America. By day it basks on the banks of rivers throughout the Amazon basin and the Pantanal wetlands before relying on its dark colouring to provide camouflage as it hunts by night.
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Though it will happily eat fish, a caiman will also take deer, feral pigs, capybaras (large rodents), snakes and all manner of domestic livestock. It has enormous patience and will lie in wait with just nostrils showing above water until an unwary prey animal comes down to drink. Then it will strike, showing immense speed and power to seize its victim and drag it into the water to drown it.
Black caimans do attack people occasionally – mostly fisherfolk. There are thought to be 50-100 attacks a year and an average of two deaths.
Bullet ant
Why is this large ant called a bullet ant? It's because it's bite is shockingly painful, likened to being shot. Victims describe waves of burning, throbbing pain that last for 24 hours – hence its alternative Venezuelan name “hormiga veinticuatro”the “24-hour ant”. A large ant species, with workers up to 3cm long, it is aggressive and predatory, feeding on any small creatures, from spiders to frogs, found on its foraging forays in the trees in the lowland rainforests of South and Central America.
The sting, delivered through a powerful bite from the mandibles, is a powerful paralyzing neurotoxic peptide found in the ant’s venom. The substance is fascinating scientists and may have the potential to be a potent painkiller.
The sting is used in initiation rites of the Sateré-Mawé people of Brazil where a young boy must wear a glove with bullet ants woven into it. He must tolerate the bites for up to 10 minutes and his whole arm may be paralysed for days after the ordeal.
Jaguar
This handsomely patterned feline is an ambush predator of forests and swamps across much of northern portion of the continent. At 2.4m long and weighing up to 150kg, the jaguar is considered one of the world's Big Cats.
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It hunts large rodents, feral pigs, deer and livestock but rarely preys on humans. Between 1950 and 2025, there were 84 attacks on humans, of which 31 were fatal. The jaguar's immensely powerful jaws mean that if it gets the chance to bite, it's likely to be lethal.
There may be as many as 165000 jaguars left in the wild in South America alone – its range extends into Central and North America though numbers are decreasing throughout its range due to habitat loss and direct hunting.
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Anaconda
No list of deadly South American creatures is complete without mention of the green anaconda. It is an enormous olive-green snake, up to 9m long and weighing 250kg, making it the world's heaviest snake. Legends abound of even larger individuals and Hollywood has capitalised with many horror films based on the species.
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It is not poisonous and instead hunts prey in the slow-moving waterways of the Amazon by entrapping them in its coils and constricting, suffocating its victims to death.
The anaconda hunts using surprise, sensing the approach of prey through scent, heat and vibrations. It lurks underwater, keeping its nostrils just above the surface to breath though it can also drop from trees to ambush prey. It has been recorded catching and eating pigs, deer, birds, turtles, capybara, caimans, and even jaguars. Once it has killed its prey, it can open its jaws wide to engulf it. After a big meal, it can go for weeks without needing to hunt.
While an anaconda could easily overpower and devour a human, there are few records of attacks.
Kissing bug
Found across much of central and northern South America, Tristoma infestans is a large 3.5cm long bug (an insect from the Order Hemiptera) that feeds on mammal blood, including that of humans.
Its elongated proboscis is adapted for piercing skin and sucking. It gets its common English name 'kissing bug' and Spanish name 'vinchuca' meaning 'barber bug' from its habit of attacking humans in vulnerable areas, especially around the mouth.
Kissing bug are often infected with a protozoan parasite called Trypanosoma cruzi and this can be transmitted to humans when the bug feeds on their blood. T cruzi causes Chagas disease, whereby it infects the heart and digestive muscles leading to fever, heart conditions and digestive disorders. Untreated, it can lead to heart failure, damage to the nervous system and death.
According to the World Health Organisation, eight million people are estimate to be infected with T Cruzi and there are 10,000 deaths a year.
Red-bellied piranha
A fearsomely toothed predatory fish, the red-bellied piranha has been dealt no favours by Hollywood. In horror films, victims fall into a piranha-infested swamp to be swarmed by the seething fish and reduced to a skeleton in seconds while the water turns red with blood.
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In truth, they are small (20-30cm long) shy fish that will quickly swim for cover if they see a human. Attacks are very rare though the bit is deep and painful.
The piranha is undoubtedly well armed – or well toothed – with a set of jaws not out of place on a Geiger Alien. It mostly hunts invertebrates, crustaceans and other fish but will feed on carcasses that end up in the water, using its sharp teeth to rip at the flesh.
The only occasions when it is known to attack humans has been when under stress, during a drought for instance when its watery environment is shrinking and food is scarce.
Golden poison frog
This tiny amphibian, just 5cm long, is considered one of the most toxic animals in the world. Found in only a small area of coastal forest in Colombia and appearing in a number of different colours from coral to green or gold, a single frog contains enough venom to kill 10 adult humans. Although scientists do not understand how the frog develops its incredible toxins, frogs raised in captivity that are not fed insects from its native habitat do not develop toxicity.
Therefore, experts believe it derives the toxin from plants carried its invertebrate prey. The frog uses the toxin purely for self defence – other animals know to steer well clear. The toxin works by attacking nerve cells leading to muscle contraction, paralysis and heart failure.
Indigenous people known as the Emberá, have long taken advantage of the frog's special power, using the toxin to tip blowgun darts for their own hunting – hence the alternative name “poison dart frog”. But the frog requires careful handling as the tip of the dart is gently rubbed along a living frog's back to extract the toxin.
South America rattlesnake
A third snake on the list – and another pit viper species famed for its extremely powerful venom. Found across northern South America and into Central America, it is a beautifully patterned reptile reaching a maximum of 1.9m long. It hunts rodents and occasionally lizards.
Known as the cascavel in Brazil, the snake is best known for its rattle, which it makes when alarmed. It creates the sound by shaking a series of loose bony rings in its tail.
Hunting at dusk, the rattlesnake is usually very shy of humans but can strike without warning and so is much feared. The venom causes facial paralysis, blurred vision, muscle pain and stiffness, and can lead to kidney failure. The only effective treatment is an immediate dose of antivenom. Recorded deaths are rare.
Biting midges and mosquitoes
South America's many wetlands and waterways are rich breeding grounds for a number of mosquito and midge species. While these provide food for a vast number of other animals, they carry diseases such as malaria. But recently, a new virus has been making a move in South America, spread by midges.
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Known as Oropouche virus, it causes rashes, headaches, nausea and body pains. In more serious cases, it causes brain inflammation leading to neurological symptoms such as lethargy and vertigo, which need extended treatment. The rapid spread of the virus is worrying medical experts in the region who fear a serious outbreak could overwhelm the continent's health services.
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Giant centipede
The Amazonian giant centipede, or scolopendra gigantea, is something you definitely wouldn't want to meet on a dark night. Unfortunately, dark spots are exactly where this giant creepy crawly likes to hide and wait for prey.
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Made up of 25 or 27 segments, with 21 or 23 pairs of legs, and exceeding 30cm, this carnivorous centipede is deadly to its victims, injecting them with a powerful venom that is toxic to mammals and insects. They have been known to hang on cave ceilings with the hope of catching unsuspecting bats.
While this type of giant centipede has been recorded as killing a human child, generally the risk to humans is low, although a bite may cause severe pain.
Top image: Vitor Marigo / Getty Images
