Cuttlefish camouflage: a quantitative study of patterning

To investigate camouflage design, we compared the responses of two species of cuttlefish (Sepia officinalis and Sepia pharaonis) with controlled but naturalistic backgrounds, consisting of mixtures of 1-mm and 9-mm diameter coloured pebbles. Quantitative analysis of image data using methods adapted from functional imaging research found differences in how the two species camouflage themselves. Whereas S. officinalis switches from background resemblance to a disruptive pattern as it moves from a fine to a coarsely patterned background particle, S. pharaonis blends the two types of pattern. We suggest that the differences may arise because S. pharaonis needs to produce camouflage that is effective when viewed over a relatively wide range of distances. (C) 2007 The Linnean Society of London.