When threatened, they rise up on their front legs and arch their back, sometimes even flipping themselves over completely, to reveal the bright red-and-black coloration of their underside.

The striking black-and-yellow western tanager, with its bright red head, is one of the more characteristic summer species of western pine forests. Although brightly plumaged, it can be quite ...

In this crime prevention poster (Central Office of Information, 1960s), the bright red suggests danger. Often black and red (or orange or yellow) appear together in nature as a warning.

This bloody discharge can vary from bright red to dark brown or black, depending on how old it is. Blood that stays in the uterus long enough will react with oxygen (oxidize). Blood that has had ...