Bears are cautious animals. They tend to avoid over-crowded areas and act only when they feel safe. In stock market terms, a bear is pessimistic on the outlook for a particular stock, industry, market or economy. Bears believe that asset prices are unsustainable and will eventually fall. They come into the ascendancy after a bull market when prices do indeed start to fall.
Specifically, a ‘correction’ becomes a ‘bear market’ when asset prices have declined by at least 20%. Although the bears may be a bit happier in such circumstances, bear markets are not much fun but they don’t last forever. The bulls do eventually return.