TL;DR A bull market is a sustained rise (optimism everywhere); a bear market is a drop of 20% or more from a recent high (fear everywhere). The animals describe the mood as much as the math.
The plain-English version
Markets trend, and traders gave the trends animal mascots. A bull market is an extended period of rising prices — confidence grows, headlines glow. A bear market is the opposite, with an official-ish threshold: a decline of 20% or more from a recent peak. Between 10% and 20% down is called a correction — painful, common, not yet a bear.
Why those animals? The folk story: a bull attacks thrusting its horns up, a bear swipes its claws down. Probably invented after the fact, universally repeated, good enough.
What they feel like from inside
Numbers undersell it. Bull markets feel like genius — everything you buy goes up, risk-taking gets rewarded, cautious people look silly. Bear markets feel like the opposite of that: every bounce fails, good news gets sold, and time slows down. The S&P 500 has historically spent far more time in bull markets, but bears (2000, 2008, 2020, 2022) do damage fast — 2008's peak-to-trough was roughly -57%.
The useful stat: bears have historically lasted months to a couple of years; bulls have run for many years. Down moves are sharper; up moves are longer.
The common mistake
Waiting for the official label to act. By the time a bear market is declared (-20% confirmed), most of the damage is often done — and some of the market's best single days historically cluster inside bear markets, near the bottom, punishing anyone hiding in cash "until things feel safe." Feeling safe is what tops feel like; feeling terrible is what bottoms feel like. The labels are rearview mirrors.
Why you care
Because every strategy gets tested by both seasons, and most beginners build their plan during a bull — then meet their actual risk tolerance during their first bear.
Educational only — not investment advice. Everyone's a bull until the bear shows up to check.