Intraspecies aggression has profound ecological and evolutionary consequences, as recipients can suffer injuries, decrease in fitness, and become outcasts from social groups. Although animals implement diverse strategies to avoid hostile confrontations, the extent to which social influences affect escape tactics is unclear. Here, we used computational and machine-learning approaches to analyze complex behavioral interactions as mixed-sex groups of mice, Mus musculus, freely interacted. Mice displayed a rich repertoire of behaviors marked by changes in behavioral state, aggressive encounters, and mixed-sex interactions. A prominent behavioral sequence consistently occurred after aggressive encounters, where males in submissive states quickly approached and transiently interacted with females immediately before the aggressor engaged with the same female. The behavioral sequences were also associated with substantially fewer physical altercations. Furthermore, the male’s behavioral state and the interacting partners could be predicted by distinct features of the behavioral sequence, such as kinematics and the latency to and duration of male-female interactions. More broadly, our work revealed an ethologically relevant escape strategy influenced by the presence of females that may serve as a mechanism for de-escalating social conflict and preventing consequential reductions in fitness.Rachel S. Clein, Megan R. Warren, Joshua P. NeunuebelbioRxiv 2024.01.12.575321; doi: https://doi.org/10.1101/2024.01.12.575321
CC-BY 4.0 International license . 630 the sequence type (Fig 7L: randomized, 1-tailed z-test, n = 1,000 iterations, z = 0.93, p = 0.18). 631 This evidence strongly supports the idea that the aggressed male might implement a bait-and632 switch tactic to escape the hostile aggressor. 633 Escaping aggressive conspecifics and avoiding costly encounters is advantageous to an 634 individuals well-being (3). If aggressed animals successfully use a bait-and-switch like 635 mechanism to escape hostile interactions and de-escalate social conflict, then fewer fights 636 should occur between male interactions. Alternatively, the bait-and-switch could aggravate the 637 aggressor and trigger an aggressive response, thus increasing the number of fights and 638 escalating costly social conflicts. To address the two possibilities, we trained a supervised 639 machine-learning classifier to detect fights (Methods). In total, 1,177 fights took place (n = 11 640
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75) throughout the recordings (first fight, median time = 641 23.20 minutes, IQR = 24.69 minutes; last fight, median time = 296.62 minutes, IQR = 11.60 642 minutes). Compared to the other sequence types, fights rarely occurred when sequence type 1 643 (bait-and-switch) was present between aggressive male interactions (Fig 7M; n = 11, type 1: 644 median = 9 fights, IQR = 7.50 fights, other types: median = 63 fights, IQR = 44 fights; Wilcoxon 645 Signed Rank Test, W = 1, p = 0.002). Additionally, relative to the total number of fights, the 646 proportion of fights following a bait-and-switch sequence was significantly lower than for the 647 other sequence types (Fig 7N, n = 11, type 1: median = 10%, IQR = 6%, other types: median = 648 61%, IQR = 25%; Wilcoxon Signed Ranked Test, W = 3, p = 0.005). These findings suggest that 649 the bait-and-switch sequence helps animals escape hostile interactions, and ultimately de650
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651 652 Discussion: 653 Animals consistently observe and monitor changes in their social environment, leading 654 to adjustments in their behavior based on the integration of sensory feedback, previous social 655 experiences, and internal states (3). Here, we implemented sophisticated, unbiased methods to 34 bioRxiv preprint doi: ; this version posted January 13, 2024. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under a
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CC-BY 4.0 International license . 656 quantify the behavior of males in groups of freely behaving mice and established aggressor657 aggressed behavioral states as a centralized framework to examine natural social dynamics. 658 We found that males use behavioral state-dependent strategies after hostile interactions to 659 escape aggressive males and de-escalate confrontations. Specifically, we observed that after 660 aggressive behaviors, the male in a submissive state was more likely to interact with a female 661 social partner (Fig 3). Brief post-aggressive male-female social interactions occurred shortly 662 after the aggressive encounter between males (Fig 3). This pattern appeared early, often, and 663 throughout the five-hour behavioral recordings, highlighting the robustness of the phenomenon 664 (Fig 6). Immediately after the interaction between the aggressed male and a female (first male665
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