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1. An applied ecology of fear framework: linking theory to conservation practice

   https://doi.org/10.1111/acv.12629  

   Gaynor, Kaitlyn M.; Cherry, Michael J.; Gilbert, Sophie L.; Kohl, Michel T.; Larson, Courtney L.; Newsome, Thomas M.; Prugh, Laura R.; Suraci, Justin P.; Young, Julie K.; Smith, Justine A. (August 2020, Animal Conservation)

   null (Ed.)

   Research on the ecology of fear has highlighted the importance of perceived risk from predators and humans in shaping animal behavior and physiology, with potential demographic and ecosystem-wide consequences. Despite recent conceptual advances and potential management implications of the ecology of fear, theory and conservation practices have rarely been linked. Many challenges in animal conservation may be alleviated by actively harnessing or compensating for risk perception and risk avoidance behavior in wild animal populations. Integration of the ecology of fear into conservation and management practice can contribute to the recovery of threatened populations, human–wildlife conflict mitigation, invasive species management, maintenance of sustainable harvest and species reintroduction plans. Here, we present an applied framework that links conservation interventions to desired outcomes by manipulating ecology of fear dynamics. We discuss how to reduce or amplify fear in wild animals by manipulating habitat structure, sensory stimuli, animal experience (previous exposure to risk) and food safety trade-offs to achieve management objectives. Changing the optimal decision-making of individuals in managed populations can then further conservation goals by shaping the spatiotemporal distribution of animals, changing predation rates and altering risk effects that scale up to demographic consequences. We also outline future directions for applied research on fear ecology that will better inform conservation practices. Our framework can help scientists and practitioners anticipate and mitigate unintended consequences of management decisions, and highlight new levers for multi-species conservation strategies that promote human–wildlife coexistence. 

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2. A left-lateralized white matter tract associated with communication in domestic dogs

   https://doi.org/10.1016/2024.09.021  

   Levin, Isabel; Sinha, Mira; Barton, Sophie; Hecht, Erin (November 2024, Current Biology)

   The ability to communicate with conspecifics is an adaptive behavior important for survival and reproduction, particularly in lineages that evolved enlarged brains and complex social behavior. In humans, language is supported by a robust, left-lateralized white matter fiber tract called the arcuate fasciculus, which links Broca’s and Wernicke’s areas, the core neocortical language regions located in the frontal and temporal lobes, respectively1. This tract is also present in chimpanzees, less substantial than in humans and either weakly leftwardly-asymmetric or not asymmetric2. Other mammalian lineages have evolved large brains, complex behavior and social communication in parallel with primates, notably including carnivores. In dogs (Canis familiaris), domestication has almost certainly involved additional selective pressures and environmental factors that have shaped the evolution and development of neural circuits for communication. We report that the dog brain possesses a large, left-lateralized white matter tract that links cortical centers for productive and receptive communication, and that this tract is positively associated with individual variation in receptive vocabulary size. 

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3. Ecological Consequences of a Millennium of Introduced Dogs on Madagascar

   https://doi.org/10.3389/fevo.2021.689559  

   Hixon, Sean W.; Douglass, Kristina G.; Godfrey, Laurie R.; Eccles, Laurie; Crowley, Brooke E.; Rakotozafy, Lucien Marie; Clark, Geoffrey; Haberle, Simon; Anderson, Atholl; Wright, Henry T.; et al (June 2021, Frontiers in Ecology and Evolution)

   Introduced predators currently threaten endemic animals on Madagascar through predation, facilitation of human-led hunts, competition, and disease transmission, but the antiquity and past consequences of these introductions are poorly known. We use directly radiocarbon dated bones of introduced dogs ( Canis familiaris ) to test whether dogs could have aided human-led hunts of the island’s extinct megafauna. We compare carbon and nitrogen isotope data from the bone collagen of dogs and endemic “fosa” ( Cryptoprocta spp.) in central and southwestern Madagascar to test for competition between introduced and endemic predators. The distinct isotopic niches of dogs and fosa suggest that any past antagonistic relationship between these predators did not follow from predation or competition for shared prey. Radiocarbon dates confirm that dogs have been present on Madagascar for over a millennium and suggest that they at least briefly co-occurred with the island’s extinct megafauna, which included giant lemurs, elephant birds, and pygmy hippopotamuses. Today, dogs share a mutualism with pastoralists who also occasionally hunt endemic vertebrates, and similar behavior is reflected in deposits at several Malagasy paleontological sites that contain dog and livestock bones along with butchered bones of extinct megafauna and extant lemurs. Dogs on Madagascar have had a wide range of diets during the past millennium, but relatively high stable carbon isotope values suggest few individuals relied primarily on forest bushmeat. Our newly generated data suggest that dogs were part of a suite of animal introductions beginning over a millennium ago that coincided with widespread landscape transformation and megafaunal extinction. 

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4. Pet dogs (Canis familiaris) re-engage humans after joint activity

   https://doi.org/10.1007/s10071-023-01774-1  

   Byrne, Molly; Horschler, Daniel J; Schmitt, Mark; Johnston, Angie M (July 2023, Animal Cognition)

   Abstract Joint intentionality, the mutual understanding of shared goals or actions to partake in a common task, is considered an essential building block of theory of mind in humans. Domesticated dogs are unusually adept at comprehending human social cues and cooperating with humans, making it possible that they possess behavioral signatures of joint intentionality in interactions with humans. Horschler and colleagues (Anim Behav 183: 159–168, 2022) examined joint intentionality in a service dog population, finding that upon interruption of a joint experience, dogs preferentially re-engaged their former partner over a passive bystander, a behavior argued to be a signature of joint intentionality in human children. In the current study, we aimed to replicate and extend these results in pet dogs. One familiar person played with the dog and then abruptly stopped. We examined if dogs would preferentially re-engage the player instead of a familiar bystander who was also present. Consistent with the findings of Horschler and colleagues (Anim Behav 183: 159–168, 2022), pet dogs preferentially gazed toward and offered the toy to the player significantly more than the familiar bystander. However, no difference was observed in physical contact. These findings provide preliminary evidence for behavioral signatures of joint intentionality in pet dogs, but future work is needed to understand whether this phenomenon extends to other contexts. 

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5. A comparison of cannabinoid receptor 1-immunoreactive axon density in the amygdala among nine primate species

   Jones, DN (January 2022, Abstracts Society for Neuroscience)

   The amygdala is a sensory integration center that plays an important role in emotional learning, behavior, and motivation. Cannabinoid signaling in the amygdala modulates aspects of anxiety, aggression, and fear in rodents via cannabinoid receptor 1, however little is known about cannabinoid signaling in the amygdala of humans and nonhuman primates. Primates are behaviorally diverse, with closely related species often displaying distinct social styles characterized by varying degrees of social tolerance and agonistic tendencies. Such behavioral differences are thought to be associated with neurochemical differences among species. Given what is known about the functional role of cannabinoid signaling in the amygdala, we tested whether relatively tolerant species, such as humans, bonobos, and marmosets, possess relatively higher cannabinoid receptor 1-immunoreactive (CB1R-ir) axon density in the basolateral amygdala. We used immunohistochemistry and stereological methods to compare CB1R-ir axon density among 47 primates representing nine species: humans (n=5), chimpanzees (n=6), bonobos (n=2), baboons (n=6), rhesus macaques (n=5), Japanese macaques (n=6), pigtail macaques (n=6), marmosets (n=5), and capuchins (n=6). The basolateral amygdala is comprised of the lateral, basal, and accessory basal nuclei. Stereological data for each nucleus was collected separately. After ruling out sex differences within each species, we used repeated measures ANOVA to evaluate species differences. The interaction (F16,76 = 5.061, p<.001) and main effects of species (F8,38 = 8.007, p<.001) and area (F2,76 = 59.616, p<.001) were all significant. However, the observedspecies differences did not support our hypothesis related to social tolerance nor did the data conform to a phylogenetic pattern. Instead, we found that while some closely related species differed from each other in a nucleus-dependent manner, some distantly related species shared unexpected similarities. Our results highlight the need for additional comparative work on the cannabinoid system from a molecular and genetic perspective. We discuss the implications of our observations with special focus on primate brain evolution and its connection to primate social style. 

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