In the 14th to the 19th centuries, wolves killed hundreds of humans every year, which may explain their prevalent role as villainous scavengers in children's stories through the ages. These days, less than a dozen people are killed by wolves annually.
Though horses are herbivores and usually very gentle with humans, the sheer volume of human/horse interaction leads to around 20 fatal accidents around the world every year...so listen to your riding instructor.
Though they be but little, ants can be pretty fierce. Fire ants are dangerous for three reasons: They rush their victims in great numbers, they bite the skin of their victims to get a strong hold and then they inject toxic venom.
Ironically, it's the skittish nature of Bambi and his kind that leads to triple-digit human deaths every year. If you're surprised by the number of deer-related fatalities, you've probably never had to swerve to avoid a deer frozen in your headlights on a dark country road.
Elephants will respect your space if you respect theirs, but elephants who feel threatened by poachers or overly aggressive tourists are known for bouts of rage; they will charge animals they view as a threat.
Don't be fooled by their sleepy nature or their portrayal as comical characters in cartoons; hippopotami are some of the most aggressive animals on the planet and will not hesitate to charge humans who get too close. More than one human per day, on average, is killed by a hippo every year.
Crocodiles are opportunistic hunters and any animal that moves in their habitat is fair game. Around 1,000 people each year are fatally attacked by crocodiles, but because crocodiles hunt in generally poorer and more remote regions, each death receives far less media attention than other, less common animal attacks.
These parasites have tiny eggs easily transferred from contaminated dirt into human mouths. The roundworm takes up residence in the small intestine and can interfere with nutritional uptake, cause tissue reactions and even lead to intestinal blockage as the worms grow larger.
Avoiding the scorpion is common sense, right? Only two kinds of scorpions have venom potent enough to kill a human being: the Israeli deathstalker and the Brazilian yellow scorpion. Children, the elderly and people with compromised immune systems are especially vulnerable to the potent neurotoxins delivered by these two arachnids.
(Tie) 7. Freshwater Snails: 10,000 people per year
It's a three-way tie for seventh place on this list of fearsome fauna. Freshwater snails release the parasite that causes schistosomiasis in tropical and subtropical freshwater. Schistosomiasis causes all sorts of problems, from rashes and digestive problems to infertility and bladder cancer.
The assassin bug transmits a dangerous parasite through its feces. The parasite, which causes a condition known as Chagas disease, immediately unleashes acute symptoms which can include severe swelling of the heart or brain. This deadly phase of Chagas disease causes around 10,000 fatalities annually.
African sleeping sickness is caused by a parasite transmitted by the tsetse fly. There is a treatment for the parasite, but because the disease primarily infects those in rural areas, proper treatment can be hard to find. Death will eventually occur after several years of infection.
Indiana Jones' healthy fear of snakes was totally warranted, as serpents are the third most-deadly creatures in the world. Though the chances of dying from a snake bite in the United States are near zero, other regions don't have immediate access to high-quality medical care.
According to the World Health Organization, mosquito bites kill 1 million people each year. Most of these are caused by malaria, though West Nile virus and dengue fever are also potentially deadly mosquito-borne diseases.