Snakes of Costa Rica: Watch Where You Step

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My first encounter with snakes in Costa Rica was exciting, if not terrifying. It also ended in a fatality, although fortunately not of the human variety.

While managing a hotel in Playa Lagartillo, Guanacaste, my wife and I lived in a second-story apartment on the hotel property. Our bedroom window looked out on the pool grounds, surrounded by palms. A couple of beautiful yellow birds, called kiskadees, had built a nest between the fronds about 20 feet from the window. We watched as the birds diligently made their home out of twigs and grass, and weeks later, we were thrilled when we witnessed the kiskadee chicks poke their tiny hungry faces out of the nest opening, looking for a meal delivery from their parents.

This is what a great kiskadee looks like, and apparently it looks “great” to certain snakes.

One morning, just as the sun was rising, we were startled awake by the sounds of our kiskadee neighbors, squeaking and squawking in terror. I jumped out of bed and looked out the window to the palm. The birds were above their nest, screaming at a menacing invader: the body of a giant brown snake was dangling from the nest – its head already inside, looking for breakfast.

Snake invader

My wife and I jolted into action, and I ran to get the hotel’s mango and orange picker, which was a length of bamboo with a piece of hooked rebar at the end. It was high enough to reach the nest and hook the snake, which I now determined was four or maybe five feet long. But before I tried to save the chicks inside, I hesitated. What was I thinking? I had no idea what species of snake this was or if it could kill me with a nasty bite. It wouldn’t be too pleased that I interrupted its breakfast, and it would have every reason to strike at me after I pulled it from the nest and it hit the ground. If only I could identify Guanacaste’s deadly snakes! The experience made me realize that knowledge of Costa Rica snakes can help you avoid painful, venomous bites and a trip to the hospital.

What snakes are found in Costa Rica?

Central America is a paradise for humans and animals, including snakes. There are 137 snake species in Costa Rica, and 22 are venomous. Most are harmless and will bite only when provoked, but Costa Rica still records almost 500 snake bites per year. The following is a list of the most venomous snakes in Costa Rica, tips on preventing snake bites, and what to do if a poisonous snake sinks its teeth into you.



When it comes to the sheer number of snake bites involving humans, the fer-de-lance (terciopelo in Spanish) can be considered one of the deadliest snakes in Costa Rica, if not the world. It has a quick, toxic bite. Fer-de-lances reproduce at an astounding rate, so they’re so common and found on hiking trails and places where there’s human traffic.

The fer-de-lance (terciopelo): Just walk away!



Bushmaster snake bites are rarer than fer-de-lance bites, but this snake’s bite is much more deadly. This snake is known in Spanish as a matabuey, meaning “ox killer.” It’s the largest viper in the world (6.5 to 10 feet long), and its venom is potent and toxic, requiring immediate medical attention. The snake uses heat-sensing pits near its nose to detect warm-blooded prey.


Central American coral snake

The Central American coral snake is one of the most venomous snakes in Costa Rica. It has stark red, yellow and black coloring. In particular, it has black, central rings bordered by thin yellow rings set between broad red rings. It’s mainly nocturnal and feeds on other snakes (even venomous ones), lizards, frogs and invertebrates. It’s not an aggressive species, although if surprised or threatened it’ll bite and release a potent neurotoxin.


Neotropical rattlesnake

Known as a cascabel in Spanish, this snake will let you know when you’re too close by rattling its tail. It’s among the largest venomous snakes in the country, growing to more than 6 feet long. Its venom is a potent neurotoxin that can affect your eyes or cause necrosis, leading to amputations near the bite zone.


Yellow-bellied sea snake

This venomous snake swims in the warm tropical waters of the Pacific Ocean. You can quickly identify it by its yellow underbelly and brown back. It lives most of its life in the ocean and prefers deeper waters away from land. However, sometimes currents will push these snakes closer to the beaches, so you need to watch out for them when you’re swimming. They have a highly venomous bite full of mycotoxins and neurotoxins that will shut down your nervous system if left untreated.

The yellow-bellied sea snake is best admired from a distance.



Also known as the southern cantil, the castellana is a rare species of pit viper that lives in the Pacific Coast dry forests of Costa Rica, Nicaragua and Honduras. It has  brown-to-orange dorsal bands and two cream-colored stripes from the snout. It hides under fallen leaves and tree trunks. Its bite isn’t as toxic as other venomous snakes in Costa Rica.


Hog-nosed pit viper

Recognizable by its turned-up snout, the hog-nosed pit viper is a smaller snake, measuring about 20 inches long. It’s locally known by its Spanish name, toboba. It will vigorously defend itself if disturbed, striking with so much force that it can leave the ground. It eats mainly rodents and lizards. No human fatalities from hog-nosed pit viper bites have been recorded.

The hog-nosed pit viper is easily recognized by its upturned nose.


Eyelash palm pit viper

This snake is easy to identify due to its golden color and scales above its eyes which resemble eyelashes. They are small snakes but will bite if threatened.

There are more venomous snakes that live in Costa Rica but are less of a threat to humans, including:

  • Jumping pit viper
  • Bird snake
  • Side stripe pit viper
  • Godman’s montane pit viper

There are also dozens of other non-venomous snakes, such as boa constrictors and king snakes, which can still inflict a painful bite if you harass them.

What is the deadliest snake in Costa Rica?

The fer-de-lance is responsible for the largest number of bites in Costa Rica by far, but it’s not the most deadly. Other snakes such as the Central American coral, or the yellow-bellied sea snake, have more toxic venoms. However, the most lethal bite belongs to the bushmaster, with a bite that can bring down livestock. Bites are rare, but extremely dangerous with a 75 percent mortality rate.

The bite of the bushmaster is probably the most lethal of any snake in Costa Rica.

How to prevent snakebite in Costa Rica

Don’t let a fear of snakes prevent you from enjoying the beautiful nature of Costa Rica. Snake bites are uncommon, and if you take simple precautions, you can avoid a nasty encounter.

You won’t find cobras in Costa Rica, but cover those ankles anyway.
  • Never wear sandals when hiking. Always wear close-toed shoes, preferably mid-calf or high ankle hiking boots.
  • If you see a snake, back away slowly — don’t approach it. Never try to pick up a snake.
  • Always follow designated hiking trails. 
  • Hike with a wildlife guide when available.

Typically, you’ll scare snakes away long before you arrive by the vibrations of your footsteps, your scent and the noises you make.

“Ojo” is the common for “eye,” but it also means “Be careful!”

Snakebite treatment in Costa Rica

If you happen to get bit by a snake, don’t panic. Costa Rica is a world leader in snake research and antivenom production. For most snake bite venoms, there’s an antidote that’ll neutralize the poison. Here are some snakebite first aid tips:

  • Clean the bite area with disinfectant.
  • Immobilize the bitten area.
  • Stay well hydrated.
  • Avoid cutting the bitten area, sucking out the venom, cold compresses or applying a tourniquet. These methods only worsen the situation or increase the risk of infection.
  • Get to a hospital or medical facility as soon as possible to receive an antivenom serum.
  • Take note of the snake’s markings and colors to relay to medical personnel.
An injectable antivenin packet.

Snakes in Costa Rica: prepare, don’t panic

Remember the snake-in-the-kiskadee-nest story? Well, despite my misgivings, I removed the snake from the nest with the fruit picker (which I don’t recommend, BTW). When it thudded on the ground, I saw with horror that the snake had half a kiskadee chick inside its mouth and had no intention of giving it up. I could only watch as nature took its course and the snake devoured its breakfast, the chick turning into an enormous bulge in the snake’s body.

I used the bamboo stick to pick up the snake (keeping it well away from me) and moved into a nearby field to continue its digestion. When I showed other, more knowledgeable residents the photos and video I took of the predator, I was told it was a lyre snake – a snake that bites but isn’t harmful to humans. It’s also highly adept at climbing.

Snakes are fascinating creatures and play a vital role in Costa Rica’s ecosystem. Human visitors and snakes can happily coexist with enough knowledge, preparedness and respect. 

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