Well that's all very good and sensible, but what about animal
We all know that sharks have an enormous sensitivity to blood in water.
To prevent attack, a good precaution is not to bleed anywhere near a shark. (Yes, this includes menstruation.)
Also: wearing a wetsuit and flapping around on a surfboard makes you look dangerously like a seal. Avoid that if you know you are near sharks If you do get attacked by sharks, all is not lost. Don't panic. Sharks have poor eyesight and explore things by biting them. Pushing or punching a shark's nose will often be enough to make it back off. Mind the teeth, they are sharp. If you do get bitten, check out how to tell if a shark has bitten your arm off. Lastly, Advice for a geek in a pool full of sharks contains good advice aimed at the Geek who finds him/herself in this predicament.
Bears are very protective of their food and young. Don't approach young bears (even if they do look cute).
While walking outdoors, avoid any carcass - It could be the bear's lunch.
Here's a handy reference node to print out and carry around with you:
Guide To Determining If You Are Constantly Being Mauled by Bears
Bears are very big and very strong. You will not be able to make yourself look big enough to scare off a bear.
If you happen to have a can of pepper spray (or similar) then it apparently makes a good deterrent.
- Polar Bear
On land Polar Bears are hard to spot (being white against a generally white background). However, polar bears spend a lot of time swimming, so your best chance when exploring the arctic is not to go in the water. Probably good advice generally unless you have some heavy duty fat deposits on the go.
Polar bears don't eat penguins. (here's why) - so to prevent polar bear attack: wear a penguin costume.
NB: I have not tried this myself. It may not work.