Summary: A recent study finds that sharks of the same species display distinct personalities, with consistent differences in boldness and stress reactivity.
Source: Wiley
New research shows individual personality differences in Port Jackson sharks
Researchers report that juvenile Port Jackson sharks (Heterodontus portusjacksoni) show consistent, individual differences in behavior. In controlled tests, some sharks were consistently bolder—more likely to leave cover and explore an unfamiliar, potentially risky environment—while others were more cautious. Likewise, individuals differed reliably in how they reacted to handling stress when briefly held out of water.
The study found that both boldness and handling stress reactivity were significantly repeatable across multiple trials. Sharks that emerged quickly in an initial trial tended to be the fastest to emerge in subsequent trials. Similarly, sharks that showed strong reactions to a handling stressor in one trial displayed similar reactivity in later trials. The research also identified a correlation between boldness and more active stress responses, consistent with the proactive-reactive coping style framework described in other vertebrates.
“This work shows that we cannot think of all sharks as the same. Each has its own preferences and behaviors, and it is likely that these differences influence how individuals interact with their habitat and other species,” said Evan Byrnes, lead author of the study published in the Journal of Fish Biology. He and his co-author emphasize that recognizing individual behavioral variation is important for understanding ecological dynamics and for effective species management.
Source: Joanne Morrison – Wiley
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Original Research: Abstract for “Individual personality differences in Port Jackson sharks Heterodontus portusjacksoni” by E. E. Byrnes and C. Brown in Journal of Fish Biology. Published online May 26, 2016. DOI: 10.1111/jfb.12993
MLA: Wiley. “Sharks Have Individual Personalities.” NeuroscienceNews. NeuroscienceNews, 27 May 2016.
APA: Wiley (2016, May 27). Sharks Have Individual Personalities. NeuroscienceNews. Retrieved May 27, 2016.
Chicago: Wiley. “Sharks Have Individual Personalities.” NeuroscienceNews. Accessed May 27, 2016.
Abstract
Individual personality differences in Port Jackson sharks Heterodontus portusjacksoni
This study examined interindividual personality differences between Port Jackson sharks Heterodontus portusjacksoni using a standard boldness assay and a handling stress test. The investigation assessed whether boldness and stress reactivity were repeatable traits in juvenile sharks and whether these traits covaried, indicating consistent coping styles. Results showed highly repeatable individual differences in both boldness and handling stress reactivity. Individuals that emerged from cover most quickly in an initial trial were consistently among the fastest in subsequent trials. Likewise, sharks that reacted strongly to a handling stressor in one trial were similarly reactive in a follow-up trial. The study also found a clear link between boldness and the form of stress response, mirroring the proactive-reactive coping style axis commonly observed in teleost fishes and other vertebrates. These findings demonstrate the presence of individual personality differences in sharks for the first time and underscore the importance of considering personality variation when studying elasmobranch behavior.
Understanding how personality shapes variation in behaviors such as prey selection, habitat use, activity levels, and responses to human disturbance has practical implications. Individual behavioral differences can influence how sharks interact with their environment, the risk they pose to or face from other species, and their responses to fishing, habitat alteration, and conservation measures. Accounting for behavioral individuality may improve management strategies for elasmobranchs and help preserve their ecological roles as top or mesopredators in marine ecosystems.
“Individual personality differences in Port Jackson sharks Heterodontus portusjacksoni” by E. E. Byrnes and C. Brown in Journal of Fish Biology. Published online May 26, 2016. DOI: 10.1111/jfb.12993
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