Biology 342 Fall 2014
Emily Merfeld & Nicolette Tapia
The Adaptive Value of Camouflage
The cuttlefish’s ability to camouflage allows the cuttlefish to effectively hide from predators. Selective pressures by nocturnal predators have led cuttlefish to camouflage on the bottom of the ocean at night; 86% of cuttlefish show this behavior at night, whereas only 3% show this behavior during the day (Hanlon 2007). Cuttlefish can distinguish between predator species, which allows them to make a decision between fleeing, camouflaging, or producing a startle display similar to that of an insect; cuttlefish, having larger brains than insects, will only produce startle displays in the presence of a small, less threatening predator (Langridge 2009). Cuttlefish predator discrimination is advanced to that point that cuttlefish can determine a predator’s visual capabilities and adapt their signaling appropriately (Stuart-Fox 2009). As a predator, the cuttlefish can also sneak up in prey unnoticed for attack. The Passing Cloud display is used to distract prey while they are attacked: dark waves move across the body, signaling “stop and look” to prey (Messenger 1968).
Cuddlefish also use displays comprising of few or many signals, to communicate, and these signals may involve chromatophores, iridophores, or leucophores (Messenger 2006). Many male cuttlefish don a distinctive zebra pattern (Figure 1) when attracting females or during agonistic encounters with other males (Adamo 1996). In this event, the darkness of the coloring on the male’s face may indicate whether or not the encounter may escalate to violence. Essentially, males are indicating with a lighter face that their intention with the display is not to start a fight, but to only indicate they are male and should not be copulated with. Males use this signal with light facial coloring to indicate they are male without having to enter a violent fight. Males also practice male-male signaling while courting females: males will show zebra patterning on the side of their body facing the female, and show female patterning on the side of their body facing the male, in order to avoid competition with the male (Norman 1999).
Figure 1. Zebra display. Image: http://nationalzoo.si.edu/Publications/Zoogoer/2011/4/Cephalopods.cfm.