Comparison of the Ontogeny of Hunting Behavior in Pharaoh Cuttlefish (Sepia pharaonis) and Oval Squid (Sepioteuthis lessoniana)

Abstract

Animals adopt various forms of hunting according to their ecological, morphological, and cognitive features, and their specific hunting skills are acquired ontogenetically in relation to these features. It is noted that cuttlefish and squid hunt prey through the elongation of tentacles used specifically to capture prey. However, these two cephalopods have different lifestyles, leading to questions such as whether hunting skill is acquired similarly after birth and whether tentacle elongation is behaviorally identical. To address these questions, we observed and compared how captive pharaoh cuttlefish (Sepia pharaonis) and oval squid (Sepioteuthis lessoniana) attack prey during their early life stages. Like the adults, S. pharaonis hatchlings used the tentacular lunge attack, whereas S. lessoniana hatchlings used the arm-opening attack. S. lessoniana began to exhibit the tentacular strike attack after 30 days of age. In addition to timing of the emergence of a specific hunting mode, some differences were observed in the physical aspect of hunting behavior. For cuttlefish, maximum tentacle length and maximum speed of tentacle elongation increased from hatching to 30 days of age and then decreased. In contrast, for squid, maximum tentacle length increased from hatching to 30 days of age and then became constant. The distance to prey was positively correlated with maximum length and speed of tentacle elongation in S. pharaonis and with maximum swimming speed in S. lessoniana. These results show that cuttlefish mainly use an ambush strategy and that squid use a pursuit strategy. Possible causes for the ontogenetic differences in hunting behavior are discussed.

Sucker formation in a bigfin reef squid: Comparison between arms and tentacles

“…lessoniana , the sucker‐producing area is not so markedly protruded and thus it is not necessary for it to be protected by lateral epithelium. This structural difference might reflect their life‐style differences: cuttlefishes are mainly benthic and they often walk on the ocean floor by using their arms, causing injuries of arm tips, while most Myopsida species are pelagic and swim in obstacle‐free waters (Sugimoto & Ikeda, 2013).…”

Evaluation of the 137Ba mass-marking technique and potential effects in the early life history stages of Sepioteuthis lessoniana

“…In the present study, 137 Ba mass marking slightly increased the ML and bodyweight of marked hatchlings in some of the experimental groups. Larger hatchling size may benefit from an increased attack speed (Sugimoto and Ikeda 2013) and a reduction in the distance required to capture prey accurately (Chen et al 1996). In addition, hatchling size is linked to vulnerability to predators (Blaxter 1986;Sogard 1997), so that larger size hatchlings would have a greater survival rate in the early life history stages.…”

Turning performance of brief squidLolliguncula brevisduring attacks on shrimp and fish

“…In the present study, initiation of strikes occurred over similar distances (0.5-1.5 mantle lengths). Sugimoto and Ikeda (2013) determined that the squid Sepioteuthis lessoniana only increased maximum swimming speed with greater distances to prey for the strike, while cuttlefish Sepia pharaonis only increased the maximum speed of the tentacles for greater distances to prey for the strike. Findings from the present study indicate that squid L. brevis use a combination of both approaches, increasing swimming speed and tentacle speed when necessary.…”