Boiling frogs

If a frog is placed in a container along with water from it's own pond, it will remain there, completely still, while the water is heated.

The frog doesn't react to the gradual increase in temperature, to the changes in it's environment, and when the water reaches boiling point, the frog dies.

However, if a frog is thrown into a container full of boling water it will jump right back out again, scalded but alive.