The 11 Most Dangerous Animals in Costa Rica

The 9 Most Frightening & Dangerous Animals in Costa Rica
dMz via Pixabay
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Despite having a human population of just five million, Costa Rica counts over 800 separate species of bird, over 200 separate species of mammal, and more than 400 separate types of reptiles and amphibians. It’s hardly a surprise that it’s consistently rated as one of the most biodiverse places on the planet! But, along with the resplendent quetzal and the lazy sloth, that means you can expect to encounter some pretty dangerous animals in Costa Rica, too.

Yep, there’s oodles to watch out for between those surf sessions down in Santa Teresa and party nights in Tamarindo, and we’re not talking about the close-out waves. From stinging bullet ants to venomous snakes, the land of gallo pinto and Pura Vida comes with a side of notorious critters that are certainly worth having on the radar.

Cue this guide to the most dangerous animals in Costa Rica. It’s a must read before you go and dive into the country’s lush tropical jungles or deep blue seas. From big cats to crocs, scary spiders and (far too many) snakes, it’s got a whole menagerie of not-so-savory beasts that have the potential to ruin that trip of a lifetime…

Bullet ants

Bullet ants found in Costa Rica
Photo by Graham Wise from Brisbane, Australia, CC BY 2.0
  • Latin name: Paraponera clavata
  • Attacks: Venomous sting
  • Treatment: Cold compress and local treatments
  • Habitat: Bases of trees, woodland, rainforest
  • Conservation status: Least Concern

It’s pretty much a given that any list of Costa Rica’s most dangerous animals will be brimming with insects. But whoever expected numero uno here to be a humble ant? Well…ask anyone who’s ever been bitten by the paraponera clavata and they’ll tell ya’ – this isn’t your usual ant!

First off, they are surprisingly large, growing up to 30mm in length at full adulthood in some cases. Secondly – and more to the point – they have a sting that rates as Pain Level Number 4 on the Schmidt sting pain index (AKA: the highest of the bunch!). It’s been described as “like walking over flaming charcoal with a three-inch nail embedded in your heel”. Not nice. Not nice at all.

Though the venom of the bullet ant is not fatal to humans, it can lead to excruciating pain that can last over 24 hours. Stings attack the nervous system and can cause swelling, tachycardia, vomiting, paralysis, seizures, and an intense fever. Incredibly, the Mawé people in Brazil still use the bullet ant as a sort of rite of passage for coming-of-age boys, during which they purposely get stung multiple times!

Fer-de-lance – arguably the most dangerous animals in Costa Rica!

A fer-de-lance snake
Photo by PCExotics via Pixabay
  • Latin name: Bothrops asper
  • Attacks: Venomous bite
  • Treatment: Antivenom
  • Habitat: Tropical lowland forests
  • Conservation status: Least Concern

Costa Rica has a lot of snakes and many of them are capable of making your life pretty miserable. However, of the four snakes currently on our list of Costa Rica’s most dangerous animals, the fer-de-lance is unquestionably the most vicious of the lot. In fact, the fer-de-lance is the most deadly snake in the whole country, responsible for nearly half of all bites and up to 30% of all hospitalizations for snakebites.

Also known as terciopelos in Spanish, these venomous snakes can grow up to two meters in length. Known to be erratic, aggressive, and unpredictable, they will attack if they feel threatened. What’s more, there’s a lot of crossover between the habitat of the fer-de-lance and human habitats in Costa Rica, since they predominantly live in lowland regions close to towns and cities.

If you do get bitten by a fer-de-lance their venom can cause all kinds of harm, starting with searing pain, swelling, fever, vomiting, and internal bleeding. Treatment can be administered with an antivenin but, if left untreated, the bite wounds can become gangrenous, which usually leads to amputation at the very least. Though deaths are rare, a bite from a fer-de-lance can be fatal.

Costa Rican coral snake

A coral snake
Photo by Reidastexturas via Pixabay
  • Latin name: Micrurus mosquitensis
  • Attacks: Venomous bite
  • Treatment: Antivenom
  • Habitat: Humid tropical forest
  • Conservation status: Least Concern

There are over eighty different species of coral snake located all over the world, and four of them live in the forests of Costa Rica. A member of the cobra family, the coral snake is instantly recognizable by its distinct striped black, yellow, and red pattern and usually grows to around a meter in length. One species that’s definitely worth mentioning on our list of the most dangerous animals in Costa Rica is the eponymous Costa Rica coral snake…

You’ll notice them because the banded colors are often far more pronounced than on other serpents in the genus. The yellow back rings are especially bold on these guys, while the tail narrows to a single point of alternating yellow and black blocks.

Attacks on humans are rare but coral snakes do carry an incredibly nasty venom that can be fatal. Thankfully, coral snakes are thought to be very reclusive, mostly nocturnal, and generally prefer to avoid confrontation. Just don’t back them against a wall!

Like the fer-de-lance, it also injects its venom through its fangs. The coral snake’s venom is a powerful neurotoxin, which attacks the victim’s nervous system, causing localized pain and a sensation similar to pins and needles. If a coral snake bite goes untreated, the victim can expect to suffer drowsiness, difficulty walking, and, at worst, complete respiratory arrest.

Eyelash viper

A yellow eyelash viper snake
Photo by Geoff Gallice from Gainesville, FL, USA, CC BY 2.0
  • Latin name: Bothriechis schlegelii
  • Attacks: Venomous bite
  • Treatment: Antivenom
  • Habitat: Humid tropical forest
  • Conservation status: Least Concern

This venomous viper gets its name from the scales that protrude over the top of its head, resembling elaborate human eyelashes. Eyelash vipers can be one of a variety of different colors, including yellow, green, and red, but are often very vibrant and distinctive. They tend to grow to just under a meter from tip to tail.

The eyelash viper is largely nocturnal and is not known to be aggressive. However, if it feels threatened, the eyelash viper won’t hesitate to defend itself. That’s not a situation that you want to find yourself in…thanks to its enormous and retractable fangs, it’s well adapted at getting its potent venom into its victim. So, keep watch when wandering Costa Rica’s forests – these guys live in the undergrowth and are often disturbed by hikers and trekkers.

The eyelash viper’s venom is hemotoxic, which means that it goes after both the victim’s nervous system and cardiovascular system. Those unlucky enough to be get bitten will need to be treated as quickly as possible. Deaths are very rare, but a bite from an eyelash viper could prove deadly if left unattended.

Brazilian wandering spider

A Brazilian wandering snake
João P. Burini, CC BY-SA 4.0 via Wikimedia Commons
  • Latin name: Phoneutria
  • Attacks: Venomous bite
  • Treatment: Antivenom
  • Habitat: Forest floor
  • Conservation status: Least Concern

As if Costa Rica’s snakes weren’t enough to worry about, then comes the monstrous Brazilian wandering spider! Yep, not content to stay in its namesake country, this genus of venomous spider has now spread right throughout Latin America, and has a single species in Central America and Costa Rica. You’ll mainly find them in forested and coastal areas near to a water source, but there’s really no telling where they get to – the clue’s in the name!

Brazilian wandering spiders are also known as banana spiders because they like to live among banana plants. As you can imagine, that makes them a big threat to workers on fruit plantations in Costa Rica, especially since they possess a deadly venom that can be fatal to humans!

You’ll certainly feel the bite of a Brazilian wandering spider straight away. You’ll also need to go in search of medical attention instantly. The vicinity of the bite will experience severe pain, and the victim will quickly undergo a host of symptoms, including nausea, fever, blurred vision, excessively high or low blood pressure, and even full body convulsions. While an untreated bite has the potential to be fatal, thankfully it is very rare for a Brazilian wandering spider to use all of its venom in a single bite.

Black widow spider

A black widow spider
Chuck Evans(mcevan)”., CC BY 2.5 via Wikimedia Commons
  • Latin name: Latrodectus
  • Attacks: Venomous bite
  • Treatment: Antivenom
  • Habitat: Forest floor
  • Conservation status: Least Concern

The term ‘black widow’ actually covers a broad range of around thirty species of spider that are found all over the world. Three types of black widow are native to Costa Rica, though, all of which have the trademark jet-black thorax spotted with bright colors. Famous for eating its mate after mating, it’s the female black widow that is the most venomous.

Black widows will only attack or bite if they feel threatened, but their venom is another neurotoxin that can be fatal. In fact, some say that the venom of the black widows that are present in the home of Pura Vida are stronger than that of rattlesnakes, so are not to be taken lightly. Usually, bites will cause dizziness, nausea, pain in the abdomen and chest, and possibly even blackouts. A black widow’s bite can also lead to paralysis of the diaphragm, making breathing very difficult. Without medical treatment, the venom will attack the victim’s nervous system and can potentially lead to death by asphyxiation.

Thankfully, black widows rarely attack humans, and fatalities are even rarer still. As with the Brazilian wandering spider, the black widow’s bite is much more threatening to young children or the elderly, and either will need urgent medical attention if they do fall prey.

American crocodile

American crocodiles in Costa Rica
Zdeněk Macháček via Unsplash
  • Latin name: Crocodylus acutus
  • Attacks: Bite
  • Treatment: Hospital attention
  • Habitat: Riparian habitats, close to river mouths, coastline and wetlands
  • Conservation status: Vulnerable

It’s not only deep in the tropical rainforests that you could encounter one of the most dangerous animals in Costa Rica. With two coastlines on two separate seas, countless rivers, marshes, and lagoons, there are some pretty grizzly creatures in the water, too. Cue the American crocodile, a sight that no surfer or beach bum strolling up the playa of Tamarindo will want to see first thing in the morning!

One of the few crocodiles to thrive in both freshwater and saltwater environments, the American crocodile is equally at home in coastal regions, mangrove swamps, and lakes. The majority of Costa Rica’s American crocodiles can be found inside the boundaries of one of the country’s many national parks. Experts in hunting by stealth and with the potential to grow to up to six meters long and weigh up to 900 kilos, the American crocodile is as deadly as they come.

Crocodile attacks on humans in Costa Rica are uncommon, though not as rare as you might think. Some recent attacks have even been fatal. There have also been a number of incidents involving surfers being attacked by crocodiles near Tamarindo on the Pacific coast, particularly up on the Playa Grande estuary. The rise of eco-tourism in Costa Rica has been partly blamed. Some tour operators have been accused of feeding the crocodiles, leading them to come into closer contact with humans.

Jaguar

A jaguar
Nickbar via Pixabay
  • Latin name: Crocodylus acutus
  • Attacks: Bite, claws
  • Treatment: Hospital attention
  • Habitat: Tropical and subtropical broadleaf forest
  • Conservation status: Near Threatened

Costa Rica is home to only a handful of wild cat species, most of which are of the cute rather than deadly kind. Amongst these are some of the more unusual wild cats, such as the ocelot, the oncilla and the margay. Also lurking in the forests of Costa Rica are two more well-known feline predators, the puma and the jaguar.

Whilst the puma is certainly capable of posing a threat to humans, the jaguar is far more dangerous of the two. The third largest of all the big cats jaguars can grow up to two meters long. Skilled hunters, jaguars are also capable of climbing trees and swimming long distances.

As their habitats are increasingly threatened by deforestation across Central and South America the national parks of Costa Rica provide jaguars with a safe area to roam. Whilst they are deadly hunters in reality jaguars pose little threat to humans. Living in incredibly remote areas of the forest and being largely nocturnal means that it’s very rare for humans to come into contact with a jaguar in Costa Rica.  

Bull sharks

Bull sharks swimming in the sea
amanderson2, CC BY 2.0 via Wikimedia Commons
  • Latin name: Carcharhinus leucas
  • Attacks: Bite
  • Treatment: Hospital attention
  • Habitat: Pacific Ocean coast and Caribbean Sea coast
  • Conservation status: Near Threatened

The waters around Costa Rica are home to a number of species of shark and amongst the most dangerous of them is the bull shark. At around nine feet long and with a deadly bite bull sharks are known for having a fiery temperament and a very short fuse. Incredibly un-fussy eaters with a very varied diet, bull sharks are considered as likely to attack humans. Whilst shark attacks in the wild are very rare they do happen.

Bull sharks (as well as tiger sharks) have attacked humans in coastal regions of Costa Rica. There have been two known attacks on surfers by bull sharks near Playa Grande on the west coast in the last ten years, with one of those proving fatal. Despite this scuba diving amongst Costa Rica’s sharks is a popular tourist activity, especially in the Cocos Island region and around the Bat Islands.

Three-striped poison dart frog

Three-striped poison dart frog
Photo by David Clode/Unsplash
  • Latin name: Ameerega trivittata
  • Attacks: Skin contact
  • Treatment: Hospital attention
  • Habitat: South Pacific rainforests
  • Conservation status: Least Concern

Exotic amphibians have long been on the decline in Costa Rica and the Americas. Severe deforestation from the Amazon up has fuelled diminishing populations – just check out the plight of the glimmering golden toad that was once abundant throughout the forests of Monteverde! However, there’s still one strange hopper and croaker that you might just encounter in the jungles of Costa Rica: The three-striped poison dart frog.

We’re not 100% sure that you’d want to, though. They might look pretty, but these guys are covered from web to snout in a potent alkaloid neurotoxin. If ingested it can cause numbness at the site of contact, severe cramping, convulsions, and even complete paralysis. The bad news here is that you don’t even have to get bitten to become a victim. Just brush past one and viola, the damage is done.

However, poison dart frogs are rare in Costa Rica. Very rare. Most live in the deep south of the Pacific side of the country, quite far from most of the tourist hotspots of Tamarindo, Arenal, and Jaco. What’s more, they are usually decorated in bright colors to warn off potential predators, with blazing lines of daffodil yellow and greenish-blue dashing down their back.

Costa Rican rattlesnake

Costa Rican rattlesnake
Photo by Meg Jerrard/Unsplash
  • Latin name: Crotalus simus
  • Attacks: Venomous bite
  • Treatment: Antivenom
  • Habitat: Tropical rainforest
  • Conservation status: Least Concern

The Costa Rican rattlesnake is just another name for one of the main venomous pit viper species that are found across Central America, ranging all the way from Mexico to the forests of the wild Darien Gap. You’ll recognize them for their distinct scaly pattern, which involves a number of odd protrusions and poking-out pieces, mainly down the left and right sides of the body.

The Crotalus simus likes dry and semi-dry tropical lowland forests. That limits it to portions of coastal and central Costa Rica, so contact with humans is more likely than with other snakes that live deeper in the rainforests.

Venom wise, these slitherers have a nasty mixture of crotoxin and neurotoxin-style stuff. The result of a bite will be markedly similar to what you’d get from a rattler in the USA. That means severe swelling and necrosis of the flesh at the site of the bite, along with interference with the blood system and even kidney failure in the most extreme cases. Yep, there’s no question it’s one of the most dangerous animals in Costa Rica!

What is the most dangerous animal in Costa Rica?

The most dangerous animal in Costa Rica is the Brazilian wandering spider. Considered to be the most toxic spider in the world, the Brazilian wandering spider’s venom is powerful enough to kill a human in just a single bite. However, we’d also add the fer-de-lance snake to that list, because it’s responsible for up to 47% of snakebites in the country.

What is the most dangerous snake in Costa Rica?

The most dangerous snake in Costa Rica is the highly venomous fer-de-lance, also certainly one of the most dangerous animals in Costa Rica as a whole. Loaded with a deadly toxin, the fer-de-lance is aggressive and commonly found throughout the country. Also, keep a watch for coral snakes. They are shy but extremely venomous.

Are there sharks in Costa Rica?

There are several species of shark found in Costa Rica’s waters and they reign as some of the most dangerous animals in Costa Rica for surfers and swimmers. Both the tiger sharks and the bull sharks have attacked and killed tourists in Costa Rica in recent years. This is also a potential hunting ground for great white sharks.

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