“Dramatic fighting by male cuttlefish for a female mate”

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Justine J. Allen, Derya Akkaynak, Alexandra K. Schnell, and Roger T. Hanlon

One male European cuttlefish (Sepia officinalis, right) inks in the face of another (center) as they compete for the right to mate with a female (left). Dark and zebra skin patterns, arm postures, dilated pupils, and even ink are aggressive signals in this species.
(Credit: Justine J. Allen, PhD, and Derya Akkaynak, PhD)

Aggression is widespread among the animal kingdom yet its causation, function and theoretical underpinnings are not well understood. In a new paper in American Naturalist, authors Allen, Akkaynak, Schnell, and Hanlon present a fortuitous field observation of intense fighting between two male European cuttlefish (Sepia officinalis) for a female in a natural setting in the Turkish Aegean Sea. The imagery recorded during this encounter (watch their video at https://doi.org/10.7301/Z0PR7SX4) enabled the authors to describe the animals' aggression in the context of game theory, using models of fighting behavior. The males engaged in a series of aggressive bouts that escalated in intensity from skin pattern and posture displays to vicious physical fighting complete with dramatic grappling, biting, and rolling.

Justine J. Allen and one of the cuttlefish.
(Credit: Derya Akkaynak, PhD)

The authors found that the male cuttlefish resolved conflict by progressing through successive phases of aggression while maintaining a similar rate of escalation. This suggests that the animals are monitoring the aggressive behavior of their opponent, rather than simply gauging their own fighting behavior. Although this conclusion is based on just one observation of wild animals, the authors cautiously suggest that this pattern of fighting behavior might follow some of the predictions of a mutual assessment strategy rather than a self-assessment strategy in this species.

Derya Akkaynak (left) and Justine J. Allen (right) on the Aegean coast of Turkey.
(Credit: Roger T. Hanlon, PhD)

These findings encourage the investigation of the intricate details of competition to further our understanding of aggressive behaviors, which are fundamental to winning both short-term contests and long-term evolutionary success. Rare and exciting field observations like these complement and guide laboratory experiments by validating or refuting previous studies. Moreover, they inspire future lines of inquiry since the best way to build our understanding of the life history of a species is to study and analyze freely behaving animals in nature. Read the Article