For generations, Nevada’s big-eyed, black-freckled Dixie Valley toad thrived in a small desert oasis, hidden from humans. But by the time scientists described it in 2017, the toad was already ...

From above, the oriental fire-bellied toad seems fairly nondescript—a green toad with black spots blending nicely with the verdant colors of its habitat. It’s not until it perceives a threat ...

When a person has black or dark-colored mucus, they may have inhaled potentially harmful pollutants. Coughing up black mucus may also be due to an underlying infection or condition. Mucus serves ...