Bearproof container
From KayakWiki
These are useful when travelling in bear country.
Bearproof containers are rigid, tough containers that a bear cannot break or open. They are typically plastic and roughly barrel shaped with no ridges or surface indentations that the bear can grip. The diameter is too large for the bear to get his jaws around. The ends are flat and close with several latches. The latches are turned with a large coin, so are unlikely to be accidently turned by the bear.
Bear canisters can be placed on the ground well away from your campsite. If the bear stumbles across one, he'll play soccer with it for a while until he gets bored. Try to make sure it's in a location that will make it impossible to roll downhill into the water.
Some bearproof containers are too large to fit into low volume kayaks (or their hatches). There are also bearproof Kevlar bags that are sold. The manufacturers claim that they are too tough to be torn by a bear.

