Research by the University of Jyväskylä in Finland demonstrates that the characteristic zig-zag pattern on an adder's back performs seemingly opposing functions, in order to protect the snake from potential predators. At first, the zig-zag pattern helps it to remain undetected. But when seen, it then provides a conspicuous warning of the snake's dangerous defence.

Most importantly, the zig-zag can also produce an illusionary effect that may hide the snake's movement as it flees. The research reveals how a single colour pattern can have multiple effects during an encounter with a predator, thereby expanding the discussion on protective colouration and anti-predator adaptations.

Visual defences

Protective colouration is one of the simplest but most effective tools that prey species use to evade predators. Typically, different colour patterns are valuable at different stages of a predation event. Some colour patterns are cryptic, obscuring the prey from being detected, as in the case of chameleons.