These “squishy” organisms inhabit different areas of the oceans across the world. With differing environments also comes a variety of predators as well as different forms of prey. The Sepiidae have evolved to possess numerous defense mechanisms to avoid being consumed, and at the same time, intelligently stalk and kill their prey. These organisms also have immense competitive behaviors for resources and potential partners.
Sepiidae are commonly eaten by top predators such as sharks and dolphins in nature, however, the Sepiidae have couple tricks up their tentacles in order to deceive these predators. The Sepiidae possess the ability to rapidly change the color, pattern, and even texture of their skins in order to avoid predation. A unique defense mechanism of young Sepiidae is to display “deimatic behavior” which is an eyespot display to startle and intimidate approaching predators. An example of the deimatic display can be seen below which is a form of crypsis. Additionally, this response has been observed to be predator-specific. Studies observed the deimatic display of Sepiidae in response to the following predators: “in none of the 24 encounters with crabs or 48 encounters with dogfish did a Sepiidae use this display, but it was shown in all but four of the 48 encounters with sea bass.” It can be inferred that through evolution, the organisms that did possess this unique trait were able to survive longer and produce more offspring compared to those who could not. In terms of resource use, the Sepiidae may produce ink to hide and distract the predators if camouflage and the deimatic response isn’t effective enough.
Further, the camouflage can serve as a hypnosis for the Sepiidaees prey and the Sepiidae may eat them while dazed. An interesting behavior has recently been observed where these intelligent organisms are “picky” with the choice of their meals. If they know that there will be a preferrable food source available later in the day, they will consume less of the other prey such as crabs and shrimp. This cycle of prey preference variation contributes to the predator-prey population cycles and stability as well. The article adds “This discovery could provide a valuable insight into the evolutionary origins of such complex cognitive ability.”
For the functional response of Sepiidae, a study was performed and the researchers suggest “a type III functional response for Sepiidae hatchlings preying on live mysids, since a peak is reached and afterwards the increase in prey density did not lead to higher consumptions.”
Sepiidae portray competitive behaviors; however, they intelligently choose their battles based on their chances of success. Dr. Schnell states the following: “If a male Sepiidae was challenged by a relatively smaller competitor, he would exhibit a range of aggressive behaviours and fighting displays. Intriguingly, if the same male Sepiidae was challenged by a relatively larger competitor, he would exhibit submissive behaviours, such as fleeing, inking or camouflage patterns” It has been observed that Sepiidae may even eat other Sepiidae.
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