It's almost Halloween, the time for orange and black: orange-and-black costumes, orange-and-black decorations, even orange-and-black candies. People favor these colors because it's a tradition. But what prompts some animals to cloak themselves in orange and black?
Probably the most renown orange-and-black creature is the tiger, several species of which still run wild in Asia. Closer to home there are ladybugs, butterflies, dragonflies, and birds that sport the same colors. Of the birds, the Baltimore Oriole is most famous —a baseball team shares its name and colors — though three other species of North American orioles are mainly orange and black: the Altimira Oriole, the Bullock's Oriole, and the Hooded Oriole.
The bright orange-and-black coloration of these birds (and the tigers) helps them stand out when they're in the open and want to be seen. Yet the coloration also helps the animals blend into their natural surroundings when they want to hide. That's because the orange-and-black pattern breaks up their outline in grasses and trees.
Meanwhile, for insects like milkweed bugs and Monarch butterflies, bold orange and black colors flash a warning to would-be predators: "Don't eat me! I'm poisonous!"
After Halloween, most orange-and-black animals disappear from the American scene for the winter. The decorations and costumes, on the other hand, won't return until next fall.