Evolution has generated a hugely diverse range of colours and patterns in nature. Bright, highly conspicuous visual displays are generally geared towards attracting mates or warning off predators, while many other animals want to avoid being seen entirely. Camouflage can use a range of visual display tricks; some simply try to match the general colour and pattern of the background, or evolve to look like an inanimate object (masquerade), while other strategies are thought to work by breaking up the animal’s outline (disruptive camouflage), or diverting the predator’s gaze away from the edge of the prey (distractive markings).
Camouflage strategies can be difficult to classify though; for example, up close the stripes on this zebra might act to disrupt its outline, or even act to “dazzle” a lion chasing after it – making it difficult for the lion to work out exactly which direction the zebra is turning. But far away these stripes might all blend together in the predators’ visual systems, allowing them to match a neutral background.
Working as part of the Sensory ecology group (previously at Cambridge University, now at Exeter University) I have used and developed a number of techniques to study visual signals: photographing prey in situ, using humans as model predators in touch-screen computer studies, and using woodland birds as predators for artificially generated prey made from cardboard.