Aposematic:
Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defences which make the prey difficult to kill and eat, such as toxicity, venom, foul taste or smell, sharp spines, or aggressive nature. These advertising signals may take the form of conspicuous coloration, sounds, odours, or other perceivable characteristics. Aposematic signals are beneficial for both predator and prey, since both avoid potential harm. [Wikipedia]
Noted in “Join a Scientist’s Undersea Adventure,” Andria Greene, Discover (March/April 2022):
Nudibranchs are invertebrates — backboneless organisms in the kingdom Animalia — that include 2,000 different species, many of which are best known for their wildly diverse and colorful appearance. But what’s beautiful to humans is to other animals an aposematic signal — a warning not to eat this creature. Nudibranchs’ bright coloration is intended to indicate unpalatability, and comes from a diet rich in animals armed with cnidocytes, the stinging cells common to sponges, anemone, and coral. Not all nudibranchs parade colorful displays; some rely on near-perfect camouflage to avoid being eaten. But coloration and camouflage can’t protect these and other underwater creatures from every threat.
