This is one of those questions that does not have an absolute answer. Anything I tell you will be my own opinion, since the criteria I use to pick the "most dangerous" or "wildest" animal might differ from the criteria someone else uses. As far as dangerous goes, I would probably pick the animal that caused the most amount of harm to humans each year. If you consider bacteria or viruses as animals, these would be by far the most dangerous animals to man. However, most people do NOT consider them to be animals, so scratch that. Many people would say man himself is the most dangerous animal, since we are most efficient at (and most interested in) killing our own kind. Aside from man himself, the SECOND animal responsible for the most harm to humans is....the mosquito. Mosquitos transmit all sorts of diseases (including malaria, dengue, encephalitis and yellow fever). However, mosquitos are insects, and so technically not animals.

In my personal opinion, the world's most dangerous and wild animal is the Great White Shark. What makes them dangerous is that when humans are in the water we have virtually no way of protecting ourselves from Great White Sharks, and we have never been able to keep them in captivity, which to me makes them very wild. Luckily, attacks from Great White Sharks are very very rare! (More people die from lawn mowers than from Great White Shark attacks!)

The world's most poisonous animal, so I'm told, is the golden poison arrow frog (Phyllobates terribilis) of Colombia. The poison is a neurotoxin and is located in the skin of the frog. However, others would claim that title belongs to the box jellyfish of Australia, which also has a very powerful neurotoxin that can kill in minutes. In Africa, a country know for its wild animals, the animal responsible for the most human deaths is the rhinocerous.

If you want to learn more about fierce animals, large and small, visit this web site: (requires Java)
http://www.tramline.com/tours/fierce/playtour.htm

For more information on Great White Sharks, visit:
http://www.pelagic.org/sharks/pelagic/greatwhiteshark.html

Hmmm.That's a complicated question. How would you measure "most dangerous"? Is it the total number of people hurt per year, the total number of people hurt per animal, the total number of contacts between a person and an animal that result in injury? Think about how these criteria for "dangerous" would change the answer. For example, according to one web site, someone seeks medical attention for a dog bite every 40 seconds in the US. There are probably only a few grizzly bear bites per year. Does this mean dogs are more dangerous? In Yellowstone National Park, more people are killed by bison than by grizzly bears. Is this because people are more likely to see bison, because people have less fear of bison, or because bison are more vicious? Often the most difficult and important part of answering a scientific question is defining exactly what you mean. For example, attacks might be due to animal behavior, human behavior, the tools of the animal (claws, poisons, size), or the liklihood that they will meet.

Can you think of any very small animals that can kill a person? (Think poisons or
allergies.)
Can you think of any big, safe animals?
In the movie "Jurassic Park" the kids said they did not have to be afraid of "veggiesaurs", but as we can see from the bison example, plant eaters can be dangerous too.
The bottom line is that you should respect all wild animals, keep your distance and not try to feed or pet them. You might not mean any harm, but they don't know that. Any wild animal can give you diseases or pests.

The animal diversity web page will give you lots of information on particular animals.
http://www.oit.itd.umich.edu/projects/ADW/

Many might argue that humans are.