Reptiles are Masters of Not Being Seen.
Their ability to remain motionless for hours, if not days, on end lends itself perfectly to remaining unseen and uneaten.
It doesn’t really matter what your colouration, if you can manage to not move or make any noise.
This male common lizard displays the typical mottled mix of dark and light dappled markings many animals use to help blend in with their surroundings. The pale back and dark flanks also create contrast which mimics light and shade in an undergrowth situation.
The adaption of the adder is a classic example of evolution in progress. The zigzag stripe perfectly mimics the bracken fronds and the shadows they cast. Again dark stripes on pale backgrounds with dappled markings in between help break up the outline of the animal.
Making yourself hard to spot helps keep you alive longer. Relying on your camouflage allows you to relax and reduces stress levels. Combine this with an armoury of super senses to help you detect approaching predators or prey and you can survive to enjoy a long and happy life.
Most reptiles are seen when they are moving. Most often by people who have managed to get relatively close to them without seeing them until the last second, by which time the animal is dashing for cover. So speed can be included in the survival weaponry.