Stingers, parasites, and booze thieves: these 10 critters can bring your adventures to an immediate halt.
1. Belize – Human Botfly

The human botfly, which inhabits the Americas between Mexico and northern Chile, attaches its eggs to the underside of mosquitoes or flies. When the mosquito lands on the skin of a pig, a dog, or — god forbid — your neck, the eggs hatch, sending the larvae burrowing down into your skin, where they grow and feast on your flesh before finally dropping out to pupate several weeks later.

Thankfully, the larvae don’t penetrate deep enough to cause significant damage, unless you count psychological trauma.

How to avoid them: When traveling through affected areas, be sure to use plenty of mosquito repellent. If you know you’ll be outside in an area with flying pests, wear protective clothing. See a doctor if you notice any bites on your body that don’t seem to heal, especially if they’re accompanied by intermittent pain that gradually worsens…or the prairie-dogging head of an insect larva.

Photo: opencage.info

2. Japan – Oo-Suzumebachi (Japanese Giant Hornet)

With enough venom in its quarter-inch stinger to disintegrate human flesh, the Japanese giant hornet is an unpleasant character to meet on your travels — especially if you’re a bee. With their powerful jaws, they are known to quickly and efficiently dismember entire colonies of honey bees, carrying off the larvae to feed their buddies back at the nest.

Found between the months of April through October all over Japan, giant hornets can be relentlessly aggressive if their nest is disturbed or if they feel threatened. These creatures are rumored to have the potential to take down a fully grown human, as their stings are said to be accompanied by a pheromone that calls for reinforcements.

Check out this video showing the Volkswagen-esque size of these critters.

How to avoid them: With a wingspan of up to 3 inches (7.6 cm), the behemoth Japanese giant hornet is pretty hard to miss as you’re walking around outdoors. In the unfortunate event that a hornet decides you’re the enemy, you can try to run, but these buggers are fast. Instead, avoid rapid movement, try not to block their flight path, and immediately regret not steering clear of their nest.

3. India – Filarial Worms

A major health concern in India and other parts of Southeast Asia, filarial worms are one of the leading causes of permanent and long-term disability in the world. The filarial worm doesn’t win any particular gross-out prizes: unlike other more famous parasitic worms, you don’t have to wind it out of your leg on a stick, it doesn’t grow to several meters long in your intestine, and it doesn’t cause rectal prolapse (don’t Google that). Rather, once these tiny worms have gotten to your innards, they head toward your lymphatic system where they hunker down and begin plotting your demise.

As if having worms crawling through your body isn’t bad enough, with enough time and a very specific immune response to them, you could end up with a nasty case of elephantiasis.

How to avoid them: As with many nasty parasites and diseases, this one is also transmitted by the mosquito. While traveling through the warm and humid environments of Southeast Asia, take the proper precautions: use insect repellent, sleep under a mosquito net, and be sure to cover up any exposed skin in buggy areas.

4. Kenya – Siafu

Photo: Axel Rouvin

Okay, if you think elephantiasis is scary, try being smothered to death by several million gigantic ants. In Central and East Africa, siafu colonies periodically leave their hills to search for food, marching in wide columns by the millions. Their disproportionately enormous jaws are powerful enough to shear through flesh, and the huge numbers of their massive swarms can suffocate a human who fails to move out of their way.

Though they may be terrifying, aggressive, and insanely large, siafu aren’t all bad — in their temporary presence, they consume just about any and all pests they encounter. When an invading column of ants enters a home or building, most people just choose to move out for a few days, knowing they’ll soon return to a pest-free home once the ants clear out.

How to avoid them: Well, for starters, if you see a gigantic moving column of ants on the ground in front of you, don’t go near them. These ants may be blind, but they can acutely smell and feel your presence. Most victims of these creatures are the sick, disabled, and unable to walk, so be sure to assist anybody who may need help moving out of the path of the siafu.

5. Queensland, Australia – Stonefish

Found along the Australian coast of Queensland and the Northern Territory, the stonefish is the most venomous fish in the world. Often burying themselves in the mud with their big fins, stonefish are extremely adept at blending in with the ocean floor thanks to their muddy booger-like color. They spend most of their time hiding and waiting for food to come swimming by — until you mistake them for a harmless rock and get stabbed in the foot by 13 sharp poisonous spines.

Photo: Kenneth Lu

The venom contained in these spines is rumored to be capable of killing a fully grown human in two hours. Myths and legends aside, there’s no argument about the fact that the sting from a stonefish causes excruciating pain, muscle weakness, and probably a considerable amount of crying like a baby.

How to avoid them: Avoid wading barefoot in waters where stonefish are known to lurk, especially around coral reefs and rocky areas. If stung, bathing the area in hot water can help reduce the pain while quickly getting to a hospital for a dose of anti-venom. And since stonefish can survive outside of water for as long as 24 hours, if you see one on the shore, don’t touch!

6. Malaysia – Leeches

While leeches aren’t normally particularly dangerous or harmful, finding yourself covered with worm-like bloodsuckers is probably not a desirable travel experience. In Malaysian Borneo, leeches are found both on the muddy forest floor and in the surrounding trees.

Leeches usually attach themselves to your skin unnoticed, thanks to anesthetic properties in their saliva. But tiger leeches — found on the leaves of lower vegetation — have a particularly painful bite, so be sure not to lean up against any trees when you’re pulling the mud leeches off your legs.

How to avoid them: While trekking through heavily infested areas, leeches can be pretty tough to avoid entirely. Leech socks — socks that come up over your pant legs and tie below the knee — while generally unfashionable, look a hell of a lot better than a bunch of leeches dangling off your legs. It’s also common practice in many Southeast Asian countries to soak raw tobacco leaves in water and apply the resulting “tea” to clothes, as it repels leeches and won’t do too much damage to fabric.

Photo: Sarah G...

7. Syria – Sand Fly

These little bugs are found in virtually every region in the world, and their tiny size makes them tough to spot and avoid. Most often, a bite from a sand fly will yield a red, itchy weal on your skin, but some gestating female sand flies carry a disease that will haunt you long after you get home.

Leishmaniasis, (sometimes referred to as “Aleppo boils”) which infects millions of people each year, is well entrenched in the Middle East and parts of the Mediterranean and Africa — especially in rural areas. The disease causes open sores and ulcers to spread over your skin, which can take months or even years to heal on their own.

How to avoid them: The best way to avoid a bite from a sand fly is to limit the time you spend around them. If you must be outdoors during the time they are most active — from dusk to dawn — be sure to cover up as much exposed skin as you can. In areas where leishmaniasis is prevalent, sleep under a mosquito net.

8. Miami, USA – Hookworms

Found in moist, warm climates, hookworms are one of the most common parasitic infections in many parts of the world. A soil-transmitted bug, these parasites are spread by the presence of fecal matter in sand or dirt. As such, they’re prevalent in areas with limited sanitation or poor sewage disposal systems, though a recent outbreak in Miami, Florida, proves that even a bit of cat shit on the beach can lead to a public health problem.

The tiny larvae of these critters get into your body through sweat glands or hair follicles on your skin. Once in, they burrow onward until they find a way into your pulmonary capillaries, breaking into your lung alveoli. Then, you cough them up your throat and swallow them back down into your small intestine, where they’ll live out the rest of their lives — eating, mating, and making babies for you to share with the world.

How to avoid them: Always wear shoes, especially if you suspect you may be walking through poop. Like other intestinal parasites, hookworms can also be transmitted orally — if you play in the dirt, be sure to wash your hands thoroughly before using them to shovel food in your mouth.

Photo: Stig Nygaard

9. Saint Kitts, Caribbean – Vervet Monkeys

Originally brought to the Caribbean as pets, vervet monkeys have become part of the landscape on Saint Kitts. Thanks to their ability to thrive in a variety of climates, vervets now outnumber humans on the island.

They’re actually even pretty cute — unless you’re a local farmer trying to make a living or you’re trying to enjoy a nice meal outdoors. With no natural predators on the island, vervet monkeys run amok, ruining the harvests of farmers and stealing booze from tourists on the beach, spawning this epic drunk monkey video.

How to avoid them: Stealing food out of the hands of bewildered humans is a learned behavior. Avoid encouraging these guys and refrain from feeding them out of your hand. Do your best to clean up after yourself, so the monkeys don’t have anything left to scavenge. And if you find your food or beverages under assault from a vervet monkey, don’t threaten or harass them, as they’ve been known to get aggressive if provoked.

10. Sydney, Australia – Sydney Funnel Web Spider

Most 8-legged creatures lurk in dark corners, scuttling away at the hint of a human presence. The Sydney funnel web spider, however, defends itself ferociously when agitated by humans, rearing up on its hind legs and exposing its massive fangs like a lunatic.

Photo: Ianmacm

Sydney funnel web spiders are known for grabbing onto their victims and delivering a series of highly venomous bites. If you’re unlucky enough to be on the receiving end of a funnel web spider bite, consider yourself in a life-threatening situation, apply a pressure bandage, and get to a hospital as soon as humanly possible.

How to avoid them: Male funnel web spiders wander in search of females, especially after rainfall, and have been known to amble into buildings and camps. If you see one floating in a swimming pool, don’t pick it up — they can survive submerged for up to 30 hours and can still deliver a nasty bite. If you’ll be gardening or walking in known funnel web territory, be sure to wear gloves and thick-soled shoes.