#10
Poison Dart
Frog

These pint sized frogs arent for kissing. Their backs ooze a slimy
neurotoxin that is meant to keep predators away. Each frog produces
enough of the toxin to kill 10 humans.
#09
Cape Buffalo

When faced with a predator, cape buffalos charge head on. Thats
1,500 pounds of beast topped off with two big, sharp horns. Youre
lucky if theres only one the real danger comes when a herd of
thousands stampedes in your direction.
#8
Polar Bear
See amongst us Bears,
the Bear is the scariest 

Sure they might look cuddly at the zoo, but in the wild they eat
elephant seals for breakfast. Get between one and its cub and it
could easily rip off your head with one swipe of its giant
paw.
#7
Elephant

Not every elephant is as friendly as Dumbo. Elephants kill more
than 500 people a year worldwide. African elephants generally weigh
in around 16,000 pounds all the better to stomp you with not to
mention their sharp tusks.
#6
Australian Saltwater
Crocodile

Dont mistake this croc for a log! It can lay still in the water,
waiting for passers by. Then, in the blink of an eye, itll lunge
at prey, pulling it under water to drown and dismember.
#5
African Lion

Giant fangs? Check. Lightning quick? That too. Razor sharp claws?
You betcha. Hungry? You better hope not. These big cats are near
perfect hunters.
#4
Great White
Shark

Blood in the water can excite these sharks into a feeding frenzy,
where theyll use all 3,000 of their teeth to bite anything that
moves.
#3
Australian Box
Jellyfish

Also known as the sea wasp, this salad-bowl sized jellyfish can
have up to 60 tentacles each 15 feet long. Each tentacle has 5,000
stinging cells and enough toxin to kill 60 humans.
#2
Asian Cobra

While the Asian Cobra doesnt hold the title of most venomous
snake, it does the most with what it has. Of the 50,000 deaths by
snakebite a year, Asian Cobras are responsible for the largest
chunk.
#1
Mosquito

Most skeeter bites just make you itch. But some mosquitoes carry
and transfer malaria causing parasites. As a result, these little
pests are responsible for the deaths of more than two million
people a year.
Taken from:
http://www.livescience.com/animalworld/top10_deadliestanimals.html