Deception has a long and distinguished history. Mimicry and camouflage are common in the animal world among predators and prey alike - to hide, to pretend to be dangerous, to lure prey into a false sense of security, etc.
Batesian mimicry occurs when two or more species are similar in appearance, but only one has the trait (e.g. being poisonous) being signaled. Coral snakes have alternating stripes of red, yellow and black. So do king snakes and milk snakes. However, coral snakes are poisonous, but king snakes and milk snakes aren't. The plain tiger butterfly is poisonous, containing alkaloids that make predators vomit. They also fake death when attack, oozing nauseating liquid, enabling them to often survive such attacks. The palatable indian frittillary females and danaid eggfly females look much like plain tiger butterflies. Alligator snapping turtles have tongues which look like worms; if a fish tries to eat such a tongue, the fish is eaten instead.
Muellerian mimicry is the same thing, except that the two species do in fact share the trait being signaled. Monarch butterflies and viceroy butterflies look much alike, and both taste bad to predators. Poison arrow frogs and Mantella frogs tend to have bright coloured spots against a black background, and they are all poisonous.
Self-mimicry is where one body part imitates another. Prey can use this to increase chances of survival if attacked, and predators can use it to lure prey into a false sense of security. Owl butterflies have spots on their wings which looks like eyes. They are more likely to survive an attack on their wings than an attack on the main part of their body. Pygmy owls have false eyes in the back of their heads to fool predators into thinking they are seen. The two-headed snake of central Africa has a head which looks like a tail and a tail which looks like a head, fooling prey into believing the attack will come from the tail rather than the head.
Camouflage involves imitating the appearance of the environment to avoid being seen by predators or prey. Katydids look like leaves or sometimes sticks. Countershading involves a light underside and a dark top, to counterbalance normal shadowing, and is employed by grey reef sharks and pronghorn antelope.
Deception is not some barbaric human invention - it is ingrained in use by evolution for a reason - because we need it, to survive. Deception is often as natural as breathing, and we lie not only to others, but to ourselves. Honesty often requires actual effort.
Notice a number of the examples above involve colour, which is not a hard signal to fake, making such signals conventional signals. Basically, it is much like signaling that you are strong by wearing a 'Weight lifter' t-shirt - not hard to fake, and if too many do fake it, the signal may become worthless.
According to the handicap principle, a signal may be difficult to fake if producing it requires the trait being signaled. Having muscles tends to require being strong, hence having big muscles is an assessment signal for being strong. Moose have large antlers, which requires strong bodies to support, hence antlers are an assessment signal for strength.
The following questionnaire is helpful: 1. What is the cost of sending the signal if honest? 2. What is the cost of sending the signal if deceiving? 3. What are the advantages to the deceiver? 4. Statistically, how reliable is the signal? (May require experimentation.) 5. What is the cost of observing the signal? 6. What is the cost of being deceived?
If the cost of sending the signal if deceiving is significantly higher than the cost of sending it if honest, and the advantages to the deceiver are not too great, it should generally be fairly reliable. However, the cost of observing the signal relative to the cost of being deceived and the reliability of the signal itself is important to deciding whether to bother.
References
* 'The Arts of Deception: Mimicry and Camouflage'. http://rainforests.mongabay.com/0306.htm * Zahavi, Amotz. 'The fallacy of conventional signaling'. 1993. http://links.jstor.org/sici?sici=0962-8436%2819930529%29340%3A1292%3C227%3AT... * Donath, Judith S. 'Identity and Deception in the Virtual Community'. Communities in Cyberspace. MIT Media Lab. 1996. http://smg.media.mit.edu/people/Judith/Identity/IdentityDeception.html