Penguins are odd birds. For one, they cannot fly (but they are amazing swimmers), and, contrary to popular belief, the majority of penguin populations live in warmer regions. Only four of the 18 penguin species regularly live and breed in frigid Antarctica; the rest live in sub-temperate to temperate regions, along the coasts or on islands in the Southern hemisphere. But these beloved birds are in danger, with populations declining up to 90 percent. Most of this decline can be attributed to human disturbances—and today the main threats are climate change and overfishing. Dyan deNapoli explains the reasons behind the decline, past and present—and why penguins are like the proverbial canary in the coal mine of our oceans. Read more about how penguin health reflects ocean health.