Animals exhibit dramatic immediate behavioral plasticity in response to social interactions, and brief social interactions can shape the future social landscape. However, the molecular mechanisms contributing to behavioral plasticity are unclear. Here, we show that the genome dynamically responds to social interactions with multiple waves of transcription associated with distinct molecular functions in the brain of male threespined sticklebacks, a species famous for its behavioral repertoire and evolution. Some biological functions (e.g., hormone activity) peaked soon after a brief territorial challenge and then declined, while others (e.g., immune response) peaked hours afterwards. We identify transcription factors that are predicted to coordinate waves of transcription associated with different components of behavioral plasticity. Next, using H3K27Ac as a marker of chromatin accessibility, we show that a brief territorial intrusion was sufficient to cause rapid and dramatic changes in the epigenome. Finally, we integrate the time course brain gene expression data with a transcriptional regulatory network, and link gene expression to changes in chromatin accessibility. This study reveals rapid and dramatic epigenomic plasticity in response to a brief, highly consequential social interaction.

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Coping styles theory provides a framework for understanding individual variation in how animals respond to environmental change, and predicts how individual differences in stress responsiveness and behavior might relate to cognitive differences. According to coping styles theory, proactive individuals are bolder, less reactive to stressors, and more routinized than their reactive counterparts. A key tenet of coping styles theory is that variation in coping styles is maintained by tradeoffs with behavioral flexibility: proactive individuals excel in stable environments while more flexible, reactive individuals perform better in variable environments. Here, we assess evidence for coping styles within a natural population of threespined sticklebacks (Gasterosteus aculeatus). We developed a criterion-based learning paradigm to evaluate individual variation in initial and reversal learning. We observed strong individual differences in boldness, cortisol production, and learning performance. Consistent with coping styles, fish that released more cortisol were more timid in response to a predator attack and slower to learn a color discrimination task. However, there was no evidence that reactive individuals performed better when the environment changed (when the rewarded color was reversed). The failure to detect trade-offs between behavioral routinization and flexibility prompts other explanations for the maintenance of differing coping styles.

In this review, we pose and respond to three questions concerning canine cognition: How has the history of this field influenced what we currently know about dog cognition? How confident should we be about what we know? Finally, what should we find out next? We begin by presenting two perspectives on canine cognition. We then survey the existing literature by conducting a quantitative summary of over 100 years of empirical work, focusing on power and replicability. Last, we lament the dearth of individual-differences studies in dog cognition (only three since 1911). We claim that a test of dog IQ with good psychometric properties will benefit basic science on dog and human health (including aging and dementia research). As a complement to an existing rich program of ethological investigation, we argue that individual-differences work on dogs should be a research priority.

A B S T R A C TFew studies have sought to describe cat elimination behavior in detail and much of the information presently available focuses on factors that potentially cause cats to reject a litter box. Thus, the ethograms published in the current veterinary and scientific literature largely focus on macro behaviors (e.g., enter box, dig, squat, cover, and exit box) and lack the detail necessary to make distinctions between types of litter box experiences for cats. To facilitate our understanding of what positive and negative litter box experiences look like for cats, we observed cats eliminating in both an enriched ("positive") and in a clinic-like ("restricted") environment. Our results reveal that cat elimination behavior is complex and may include up to 39 different behaviors expressed during urination and defecation events. We further evaluated each event, examining the behaviors occurring pre-, during, and post-elimination as a means to better understand the behaviors associated with the appetitive, consummatory, and post-consummatory phases of the reward cycle around elimination. In doing so, we found clear differences in behavior at different stages of the elimination sequence between our two environments. In general, the elimination sequence was prolonged in the clinic-like environment compared to the enriched environment (P < 0.005) and most of the extra time was spent interacting with the box post-elimination (P < 0.005). In the clinic-like environment cats were hesitant to enter the box, spent a considerable amount of time pawing at surfaces other than the litter (P < 0.02) and spent a great deal of time sniffing eliminations postelimination (P < 0.005). In addition, cats in the clinic-like environment had less frequent urination events and their events were longer in duration than when in the enriched environment (P < 0.0039). Thus, although seemingly counterintuitive, a relatively brief elimination sequence may be indicative of a more positive litter box experience. In addition, when given the opportunity cats will utilize a large amount of space during their elimination sequence. Despite popular perception that cats will immediately turn to out-of-box elimination if they are dissatisfied with their litter box environment, we discovered that cats will continue to use a box (and not eliminate outside the box) even when their behavior is indicative of frustration.