Anything bright or contrasting, like bright red on black, for instance. The most common colors tend to be neon-like yellows, greens, blues, and reds.
Warning colors prevent some animals from being eaten because their bright colors serve as a warning. The colors signify to predators that eating the animal will cause them to become ill or hurt.
Red,Yellow and blue
Colors
Cuttlefish use warning colors to say stay away from me or to intimidate other animals
A warning color is a color that an animal uses to warn enemies that it is not safe to eat. Most animals that use color as a defence attempt to blend into their environment as much as possible (camouflage). Warning colors are the opposite. Animals displaying warning colors are bright and stand out. They are sending the message 'look at me, I don't need to hide from you because I know you can't hurt me.' Most animals display these warning colors to declare that they are poisonous and should never be eaten. Some animals display bright colors that appear to be warning colors, yet they are not poisonous. These are imitators - by pretending to be poisonous they can often deter most predators without going to the effort of producing venom.
Bright colors such as red, yellow, lime green
US standard traffic warning signs are yellow background with black symbols or letters. Traffic warning signs in other countries are generally white or yellow background with a red or black border in a triangular shape. Industrial warning signs are various colors, including OSHA and ANZI standards with orange background and black lettering. A yellow OSHA or ANZI sign would mean "caution" not "warning".
Anything bright or contrasting, like bright red on black, for instance. The most common colors tend to be neon-like yellows, greens, blues, and reds.
Three examples of warning coloration are the blue poison dart frog, certain snakes (rattlesnakes), and the Yellow-winged darter dragonfly.
Many animals have colors that allow them to blend in with their surroundings or background, as if they were wearing camouflage. Littleuni: Also, some animals have very bright colors which is a warning to predators that they are poisonous.
Animals with brighter colors are said to be more dangerous or poisonous. So, a bright colored display is a warning to predators to stay away.
Flash coloration is a type of warning signal that animals will signal when they feel threatened. (As opposed to constant warning colors.) The sudden flashes of bright colors can serve to intimidate, distract, or confuse predators. A ring neck snake, for example, may flash its bright orange belly when threatened, event though it normally seems black or brown colored.