SNAKE
The Danger: While not every snake is poisonous, you don't want to take chances.
Survive It: Don't try to kill it! Back away slowly and give it a wide berth—it strikes fast. Already been bitten? Sucking out the venom is a myth. Stay calm (hard to do but very important), tie off the affected area to quarantine the poison, and walk (don't run) to get help.

MOSQUITO
The Danger: Tiny, pesky—and deadly. All it takes is one sting from a malaria-ridden insect and a lifetime of fevers is just a short time away.
Survive It: With proper treatment you won't die, but malaria never really goes away. Start the antimalarials before you leave home and continue popping pills for a month after your return. And of course, bring plenty of DEET-containing repellent.

CROCODILE
The Danger: These prehistoric creatures will try to disable their prey by getting a firm, biting grip, submerging, and performing a long, fast barrel-roll. In other words, if it's got you, fuhgetaboutit.
Survive It: About the only way to get a croc to let go of you is to punch him in the nose or poke him the eye. And that won't always work. There are reports of people lifting up a croc's tongue so they get a lung-full of water while underwater. But if you have the sense to do this while being attacked, you're more coordinated than us.

FIRE ANT
The Danger: Tiny but aptly named—you don't want these soliders to get in your shorts. They've been known to actually devour small animals.
Survive It: Lose your clothes—fast. You can try jumping into water, but you'll likely have to extract their huge pincers from your skin one by one. Keep them from your tent in the first place by pouring the cold ashes from a fire around the tents or eating area. They won't crawl over the ash.