Predator Avoidance Strategies
As well as being able to use fast jetting to escape from predators, cephalopods have evolved some unique strategies to avoid and deter predators. They are well known for their ability to rapidly change the colour, pattern and even the texture of their skin in order to camouflage themselves and are able to do this against a huge variety of backgrounds (Hanlon 2007).
Some cuttlefish (Sepia spp.) have shown a preference for burying themselves in soft substrate (Allen et al. 2010) and some benthic octopus (Octopus spp) have adopted the use of dens or lairs for protection and shelter (Boyle and Rodhouse 2005). I. notoides is known to attach to the underside of seaweed and seagrass fronds (Norman and Reid 2000; personal observation) (see video below) and it has been suggested that strategies such as these may be less energetically costly than producing camouflage effects, but this has yet to be tested (Hanlon et al. 1999).
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I. notoides using its adhesive organ to attach to a seaweed (Caulerpa sp.) frond in the laboratory. Video by Samantha Reynolds
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Most coleoid cephalopods (all extant groups except the nautiloids) have an ink sac complex which produces a dark coloured liquid made of suspended melanin granules. This ink can be excreted by the animal when under threat and creates a dark cloud to obscure its escape. The ink is alkaloid and it is thought that it may deter predators, such as fish, by anaesthetising their chemoreceptors (Ruppert et al. 2004). The ejection of a dark brown ink was observed in I. notoides in the lab when trying to escape from nets being used to catch animals for transfer between tanks. |