Butterflies, with their brilliant colors and elegant flight, add infinite vitality to nature. However, some species of butterflies are poisonous. Knowing how to tell whether a butterfly is venomous is an important skill for nature lovers and professionals working with insects. First, observe the color and pattern of the butterfly. Some venomous butterflies often have bright colors and eye-catching patterns, which are biological warning colors to warn potential predators. For example, some poisonous poisonous butterflies are brightly colored and contain highly toxic poisons that can harm predators.