Seminar Details

Capacities and limitations of marine animal camouflage using cephalopods as a model




Noam Josef - Ben Gurion University of the Negev; and The Interuniversity Institute of Eilat


Living under intense predation pressure, spurred cephalopods to develop an impressive dynamic camouflaging capability. Using this unique and effective trait, these animals can defense against predators ,approach prey and communicate. In my upcoming seminar at the IUI, I will present my PhD work using image analysis with behavioral experiments and field observation to identify and quantify the appearance and limitation of their capabilities. During my first study (Josef et al., 2012), I questioned wither an octopus use general resemblance and reproduce characteristics of its entire surroundings, or does it imitate a specific object in its immediate environment? Using image analysis algorithms, we examined correlations between octopuses and their backgrounds. Field experiments show that when camouflaging, Octopus cyanea and Octopus vulgaris base their body patterns on selected features of nearby objects rather than attempting to match a large field of view. Considering the mentioned conclusions from my first study - led me to think about the way cephalopods perceive their surroundings, which brought me closer to my next study about Cuttlefish depth perception (Josef et al., 2014). In this work I used a set of patterns, which creates an optical illusion to explore if cuttlefish (Sepia officinalis) utilizing texture gradient as a depth perception cue. Lastly, during my work with cephalopods over the years, I encountered their unique behavior of camouflaging during movement, which became the focus of my last study on the ability of cephalopods to camouflage during movement and over changing backgrounds (Josef et al. 2015).

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