A review of cuttlefish camouflage and object recognition and evidence for depth perception

Abstract

SummaryCuttlefishes of the genus Sepia produce adaptive camouflage by regulating the expression of visual features such as spots and lines, and textures including stipples and stripes. They produce the appropriate pattern for a given environment by co-ordinated expression of about 40 of these 'chromatic components'. This behaviour has great flexibility, allowing the animals to produce a very large number of patterns, and hence gives unique access to cuttlefish visual perception. We have, for instance, tested their sensitivity to image parameters including spatial frequency, orientation and spatial phase. One can also ask what features in the visual environment elicit a given coloration pattern; here most work has been on the disruptive body pattern, which includes welldefined light and dark features. On 2-D backgrounds, isolated pale objects of a specific size, that have well-defined edges, elicit the disruptive pattern. Here we show that visual depth is also relevant. Naturally, cuttlefish probably use the disruptive pattern amongst discrete objects, such as pebbles. We suggest that they use several visual cues to 'identify' this type of background (including: edges, contrast, size, and real and pictorial depth). To conclude we argue that the visual strategy cuttlefish use to select camouflage is fundamentally similar to human object recognition.

Camouflage and Perceptual Organization in the Animal Kingdom

“…The level of expression of each component can be varied in a continuous manner (Kelman et al 2008). Our unpublished principal components analysis of the coloration patterns displayed on a large range of natural backgrounds indicates that there are at least six degrees of freedom in the range of cryptic patterns produced by cuttlefish (see also Crook et al 2002).…”

“…Chiao et al 2007;Zylinski et al 2009a,b). This work is reviewed elsewhere (Kelman et al 2008;Hanlon et al 2011;Zylinski & Osorio 2011), but the main conclusions are as follows. Regarding low-level image parameters, cuttlefish are sensitive to mean reflectance, contrast, spatial frequency and spatial phase (Kelman et al 2008).…”

“…This work is reviewed elsewhere (Kelman et al 2008;Hanlon et al 2011;Zylinski & Osorio 2011), but the main conclusions are as follows. Regarding low-level image parameters, cuttlefish are sensitive to mean reflectance, contrast, spatial frequency and spatial phase (Kelman et al 2008). They are sensitive to orientation, but this affects the body and arm orientation rather than the pattern displayed (Shohet et al 2006;Barbosa et al 2011).…”

“…Cuttlefish are sensitive both to the presence of local edges (Zylinski & Osorio 2009a,b), and whether the spatial organization of local edge fragments is consistent with the presence of objects (Zylinski et al 2012). Cuttlefish are sensitive to visual depth, and pictorial cues consistent with visual depth (Kelman et al 2008). Often the contrast of the coloration patterns is varied to approximately match the contrast in the background (Kelman et al 2008;Zylinski et al 2009a).…”

“…Cuttlefish are sensitive to visual depth, and pictorial cues consistent with visual depth (Kelman et al 2008). Often the contrast of the coloration patterns is varied to approximately match the contrast in the background (Kelman et al 2008;Zylinski et al 2009a). Despite their mastery of camouflage cuttlefish are colour-blind, having only one visual pigment (Marshall & Messenger 1996;Mäthger et al 2006), but this deficiency seems to have little detriment for camouflage , presumably because reflectance spectra of their natural backgrounds have a simple and predictable form (the monotonic slopes of yellows-through-browns), where reflectance increases linearly with wavelength and, as such, the colour is well predicted by luminance.…”