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2018

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Articles 241 - 270 of 310

Full-Text Articles in Terrestrial and Aquatic Ecology

Omnivore Density Affects Community Structure Through Multiple Trophic Cascades, Donald J. Benkendorf Jan 2018

Omnivore Density Affects Community Structure Through Multiple Trophic Cascades, Donald J. Benkendorf

Murray State Theses and Dissertations

Omnivores can dampen trophic cascades by feeding at multiple trophic levels, yet few studies have evaluated how intraspecific variation influences the effect of omnivores on community structure. The Speckled Dace (Rhinichthys osculus) is an omnivorous cyprinid that consumes algae and invertebrates and is abundant throughout the western United States. I sought to identify the effects of size and size structure on top-down control by dace and learn how these effects scaled with density. Dace were manipulated in a mesocosm experiment and resulting changes in invertebrate and algal communities and measures of ecosystem function were monitored. Omnivores affected experimental …

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Sentient Plants? Nervous Minds?, Arthur S. Reber Jan 2018

Sentient Plants? Nervous Minds?, Arthur S. Reber

Animal Sentience

The commentaries by Calvo (2018) and Mallatt & Feinberg (2017) on my 2016 target branch out from a common conceptual node like forks in a road. Calvo criticizes me for not acknowledging that plants too are likely to be sentient and claims I have fallen into the kind of category error of which I accuse others ─ a zoocentric bias that fails to grant consciousness to flora. Mallatt & Feinberg maintain that I've gone too far in granting sentience to any species that lacks a nervous system. Calvo makes some good points but there are other issues concerning plant sentience …

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Identification Of Taxonomic And Functional Ichthyofaunal Zones Within The James River Basin, Virginia, Joseph L. Noel Jan 2018

Identification Of Taxonomic And Functional Ichthyofaunal Zones Within The James River Basin, Virginia, Joseph L. Noel

Theses and Dissertations

Environmental gradients structure ichthyofaunal communities longitudinally along river networks via the selective filtering of species’ traits. In many instances, these environmental influences have created distinct zones of co-occurring fish species. Zonation studies have most often been conducted with taxonomic data (species x site matrices), but the increasing availability of functional trait data creates an opportunity to build more rigorous understanding of species’ co-occurrence patterns. Notably, zonation studies that use taxonomic data may not reveal the same patterns as studies based on trait data. In this study, we tested for distinct ichthyofaunal zonation in James River Basin, VA using a combination …

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Anthropocentrism As Cognitive Dissonance In Animal Research?, Ellen Furlong, Zachary Silver, Jack Furlong Jan 2018

Anthropocentrism As Cognitive Dissonance In Animal Research?, Ellen Furlong, Zachary Silver, Jack Furlong

Animal Sentience

Harmon-Jones et al. (2017) make a thought-provoking suggestion in their commentary on Zentall (2016): Overlooked biases among researchers on animal cognition might lead them to discount the traces of higher-order cognition in animals they study. We find the suggestion both philosophically important and worth further reflection for animal scientists. Harmon-Jones et al. point to two “cognitive dissonance” biases involving the clash between the common human resistance to viewing ourselves as animals/meat-eaters and how these biases might lead to discounting possible advanced cognitive performances in the animals studied. We show how these biases might appear in cognitive research generally and argue …

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Diversity Of Water Bugs In Gujranwala District, Punjab, Pakistan, Muhammad Shahbaz Chattha, Abu Ul Hassan Faiz, Arshad Javid, Irfan Baboo, Inayat Ullah Malik Jan 2018

Diversity Of Water Bugs In Gujranwala District, Punjab, Pakistan, Muhammad Shahbaz Chattha, Abu Ul Hassan Faiz, Arshad Javid, Irfan Baboo, Inayat Ullah Malik

Journal of Bioresource Management

Water bugs fall under the order Hemiptera, suborder Heteroptera, which is further divided into two types, i.e., semi-aquatic (Gerromorpha) and true water bugs (Nepomorpha). They play a vital role as biological control agents and also a source of food for fishes, birds and other aquatic organisms. The present work was carried out to ascertain aquatic Hemiptera in different lentic and lotic water bodies of various sizes in Gujranwala district, Pakistan. A total of 10 species belonging to five families were identified. Species include Nepa ruber Linnaeus, Laccotrephes elongatus Montandon, Ranatra filiformis Fabricius (Nepidae), Corixa substriata Uhler, Micronecta proba …

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Can They Suffer?, Todd K. Shackelford Jan 2018

Can They Suffer?, Todd K. Shackelford

Animal Sentience

We should treat sentient nonhuman animals as worthy of moral consideration, not because we share an evolutionary history with them, but because they can suffer. As Chapman & Huffman (2018) argue, humans are not uniquely disconnected from other species. We should minimize the suffering we inflict on sentient beings — whether human or nonhuman — not because they, too, are tool-makers or have sophisticated communication systems, but because they, too, can suffer, and suffering is bad.

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Predictors Of Fish Assemblage Structure And Dynamics In Atlantic Coastal Plain Streams, Rebecca Scott Jan 2018

Predictors Of Fish Assemblage Structure And Dynamics In Atlantic Coastal Plain Streams, Rebecca Scott

College of Graduate Studies: Theses & Dissertations

Effective management of freshwater fishes requires a mechanistic understanding of the drivers of assemblage composition; in other words, what determines who is where and when. Stream fish assemblages are potentially influenced by environmental factors that act on multiple spatiotemporal scales, but the relative influence of these drivers may vary between geophysically distinct regions. This study sought to determine the patterns and drivers of fish taxonomic and functional assemblage composition in the coastal plain, a region possessing unique hydrologies, faunas, and physiochemical conditions. I addressed this goal using two complementary chapters, both of which utilized environmental and biotic data collected from …

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Comparison Of Three Benthic Macroinvertebrate Passive Sampling Devices For Non-Wadeable Streams, Kelsey A. Laymon Jan 2018

Comparison Of Three Benthic Macroinvertebrate Passive Sampling Devices For Non-Wadeable Streams, Kelsey A. Laymon

College of Graduate Studies: Theses & Dissertations

Rivers and streams provide essential ecosystem services to the degree that the monitoring and maintenance of these systems becomes imperative. Biomonitoring provides managers and policymakers with the tools to make informed decisions, and macroinvertebrates are often the object of biomonitoring because they are ubiquitous in most systems and are known to be good indicators of water quality. However, methods for sampling macroinvertebrates in non-wadeable streams (i.e., large rivers) have not been standardized across states and regions and an established method for macroinvertebrate biomonitoring in large rivers of Georgia is not currently available. My study compared macroinvertebrates collected with three types …

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Ecological Uncertainty Influences Vigilance As A Marker Of Fear, Laurence E. A. Feyten, Grant E. Brown Jan 2018

Ecological Uncertainty Influences Vigilance As A Marker Of Fear, Laurence E. A. Feyten, Grant E. Brown

Animal Sentience

We expand on the factors that may shape the predictability of risk and the potential impacts on the links between vigilance and fear, primarily in aquatic prey communities. Uncertainty in predation risks has been shown to induce increased levels of neophobia among prey. As a result of this phenotypically plastic response, prey are faced with risk assessment cues that may vary widely in their reliability. We argue that decomposing predictability may provide useful insights into the relationship between vigilance and fear.

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Competing Activities As Measures Of Fear And Vigilance, Ferenc Mónus Jan 2018

Competing Activities As Measures Of Fear And Vigilance, Ferenc Mónus

Animal Sentience

In animal behavioural research on vigilance, visual signs of alertness are usually used to estimate perceived risk (an internal “fear” state) of free-ranging animals. Different measures of vigilance and competing activities (e.g., predator vigilance, conspecific vigilance, feeding, food handling) provide clues for better understanding vigilance behaviour. How efficiently does an animal in a vigilant/non-vigilant posture devote attention to threats or invest in other activities, such as searching for or handling food? Several species regularly withdraw to a sheltered spot when feeding in an abundant food patch, spending short periods in complete safety. Frequencies of feeding interruptions or false-alarm flights provide …

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Compression And Relaxation Of Fishing Effort In Response To Changes In Length Of Fishing Season For Red Snapper (Lutjanus Campechanus) In The Northern Gulf Of Mexico, Sean P. Powers, Kevin Anson Jan 2018

Compression And Relaxation Of Fishing Effort In Response To Changes In Length Of Fishing Season For Red Snapper (Lutjanus Campechanus) In The Northern Gulf Of Mexico, Sean P. Powers, Kevin Anson

University Faculty and Staff Publications

A standard method used by fisheries managers to decrease catch and effort is to shorten the length of a fishery; however, data on recreational angler response to this simple approach are surprisingly lacking. We assessed the effect of variable season length on daily fishing effort, measured by using numbers of boat launches per day, anglers per boat, and anglers per day from video observations, in the recreational sector of the federal fishery for red snapper (Lutjanus campechanus) in coastal Alabama. From 2012 through 2017, season length fluctuated from 3 to 40 d. Daily effort, measured by using mean number of …

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Distance Models As A Tool For Modelling Detection Probability And Density Of Native Bumblebees, Darin J. Mcneil, Clint R. V. Otto, Erin L. Moser, Katherine R. Urban‐Mead, David E. King, Amanda D. Rodewald, Jeffery L. Larkin Jan 2018

Distance Models As A Tool For Modelling Detection Probability And Density Of Native Bumblebees, Darin J. Mcneil, Clint R. V. Otto, Erin L. Moser, Katherine R. Urban‐Mead, David E. King, Amanda D. Rodewald, Jeffery L. Larkin

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

Effective monitoring of native bee populations requires accurate estimates of population size and relative abundance among habitats. Current bee survey methods, such as netting or pan trapping, may be adequate for a variety of study objectives but are limited by a failure to account for imperfect detection. Biases due to imperfect detection could result in inaccurate abundance estimates or erroneous insights about the response of bees to different environments. To gauge the potential biases of currently employed survey methods, we compared abundance estimates of bumblebees (Bombus spp.) derived from hierarchical distance sampling models (HDS) to bumblebee counts collected from fixed‐area …

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An Historical Overview And Update Of Wolf-Moose Interactions In Northeastern Minnesota, L. David Mech, John Fieberg, Shannon M. Barber-Meyer Jan 2018

An Historical Overview And Update Of Wolf-Moose Interactions In Northeastern Minnesota, L. David Mech, John Fieberg, Shannon M. Barber-Meyer

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

Wolf (Canis lupus) and moose (Alces americanus) populations in northeastern Minnesota, USA, have fluctuated for decades and, based on helicopter counts, moose numbers declined to a new low from 2006 to about 2012. Other steep declines were found in 1991 and 1998 during periods when moose counts were done with fixed-wing aircraft; these declines also appeared to be real. Winter wolf numbers, monitored in part of the moose range, had been increasing since about 2002 to the highest population in decades in 2009. However, from 2009 to 2016, wolves decreased precipitously, and the moose- population decline leveled …

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Predator Presence And Size Variation Alters Community Structure Through Multiple Trophic Cascades, Robin Baker, Howard Whiteman Ph.D. Jan 2018

Predator Presence And Size Variation Alters Community Structure Through Multiple Trophic Cascades, Robin Baker, Howard Whiteman Ph.D.

Murray State Theses and Dissertations

Predation plays a crucial role in shaping community structure and can initiate trophic cascades that can alter abundances across adjacent trophic levels. Recent research has suggested that variation among individual predators may have stronger effects on ecological dynamics than previously appreciated. Intraspecific variation within predators could lead to differential levels of top-down control with implications for trophic cascade strength. In this experiment, we manipulated the body size variation of predatory mole salamanders (Ambystoma talpoideum) within experimental mesocosms and monitored a suite of abiotic and biotic response variables. We predicted that predator populations with increased body size variation would …

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Resource Selection Of Free-Ranging Horses Influenced By Fire In Northern Canada, Sonja E. R. Leverkus, Samuel D. Fuhlendorf, Marten Geertsema, Brady W. Allred, Mark Gregory, Alexandre R. Bevington, David M. Engle, J. Derek Scasta Jan 2018

Resource Selection Of Free-Ranging Horses Influenced By Fire In Northern Canada, Sonja E. R. Leverkus, Samuel D. Fuhlendorf, Marten Geertsema, Brady W. Allred, Mark Gregory, Alexandre R. Bevington, David M. Engle, J. Derek Scasta

Human–Wildlife Interactions

Free-ranging or feral horses (Equus ferus caballus) were important to the livelihood of First Nations and indigenous communities in Canada. The early inhabitants of the boreal region of British Columbia (BC) capitalized on naturally occurring wildfires and anthropogenic burning to provide forage for free-ranging horses and manage habitat for wildlife. This form of pyric herbivory, or grazing driven by fi re via the attraction to the palatable vegetation in recently burned areas, is an evolutionary disturbance process that occurs globally. However, its application to manage forage availability for free-ranging horses has not been studied in northern Canada. Across Canada, there …

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The Three Creeks Allotment Consolidation: Changing Western Federal Grazing Paradigms, Taylor Payne Jan 2018

The Three Creeks Allotment Consolidation: Changing Western Federal Grazing Paradigms, Taylor Payne

Human–Wildlife Interactions

The federal government owns approximately 47% of all land in the western United States. In the state of Utah, about 64% of the land base is managed by the federal Bureau of Land Management (BLM) and the U.S. Forest Service (USFS). The government has historically issued permits to owners of private lands to allow the owners to graze their livestock on public lands. The permits (allotments) are generally of 10-year duration and allow for an annual season of use. In some cases, continued and repeated historical annual grazing practices may not be ideal for permit holders and their communities nor …

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Ecological Implications Of Foraging And Life-History In Three Cold-Adapted Species, Andrew Von Duyke Jan 2018

Ecological Implications Of Foraging And Life-History In Three Cold-Adapted Species, Andrew Von Duyke

Dissertations, Master's Theses and Master's Reports

This research investigates the ecology of: ringed seals (Pusa hispida), moose (Alces alces), and bowhead whales (Balaena mysticetus). Each of these species draws upon specialized strategies to meet the physical demands of life in their extreme environments. However, they are currently experiencing unprecedented changes in their habitats. This work adds to what is known about the behavior, physiology, and population dynamics of cold-adapted species—providing insights of value for an improved understanding of foraging and life-history theory, and informing conservation and ecosystem monitoring efforts. Chapter 1 provides a brief introduction to the scope of work …

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Vertical Distribution Of Meroplankton And Bivalve Competition In A Well-Mixed Estuary, Jennifer M. Raabe Jan 2018

Vertical Distribution Of Meroplankton And Bivalve Competition In A Well-Mixed Estuary, Jennifer M. Raabe

UNF Graduate Theses and Dissertations

If we want to understand how meroplankton utilize the water column and how their vertical distribution may influence horizontal advection, it is important to study their behavior in the various environments where they exist. In a well-mixed system with physical cues dampened, and no vertical layering, these organisms will have to depend on environmental cues such as light, tidal current, and tide cycle, as well as their own swimming ability to migrate vertically. Plankton and water samples were collected at three depths (near surface, midwater, near bottom) during the summers of 2013 and 2014 from sites within the main channel …

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Jealousy In Dogs? Evidence From Brain Imaging, Peter Cook, Ashley Prichard, Mark Spivak, Gregory S. Berns Jan 2018

Jealousy In Dogs? Evidence From Brain Imaging, Peter Cook, Ashley Prichard, Mark Spivak, Gregory S. Berns

Animal Sentience

Domestic dogs are highly social and have been shown to be sensitive not only to the actions of humans and other dogs but to the interactions between them. We used the C-BARQ scale to estimate dogs’ aggressiveness, and we used noninvasive brain imaging (fMRI) to measure activity in their amygdala (an area involved in aggression). More aggressive dogs had more amygdala activation data while watching their caregiver give food to a realistic fake dog than when they put the food in a bucket. This may have some similarity to human jealousy, adding to a growing body of evidence that differences …

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Researchers, Not Dogs, Lack Control In An Experiment On Jealousy, Jennifer Vonk Jan 2018

Researchers, Not Dogs, Lack Control In An Experiment On Jealousy, Jennifer Vonk

Animal Sentience

Cook and colleagues (2018) have developed a clever method to measure fMRI in awake dogs in response to a number of interesting stimuli. As a result, they are able to determine neural correlates of observable behavior. They report that dogs may experience something akin to jealousy because they show greater amygdala activation in response to food being given to a fake dog versus food being placed in a bucket. However, several critical controls are missing which prevent the authors from being able to speak of jealousy.

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Finding The Green-Eyed Monster In The Brain Of A Dog, Peter Singer Jan 2018

Finding The Green-Eyed Monster In The Brain Of A Dog, Peter Singer

Animal Sentience

That dogs show behavior suggestive of jealousy has long been known and has been demonstrated under controlled conditions. Cook et al. have now shown arousal in the amygdala when dogs see a caregiver feeding another dog. This finding has ethical significance in two respects. First, the consideration shown by the investigators for the welfare of their experimental subjects sets an example for other researchers using animals. Second, the greater understanding of the emotional lives of animals should lead to more concern for their needs.

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What Can The Social Emotions Of Dogs Teach Us About Human Emotions?, Dean Mobbs Jan 2018

What Can The Social Emotions Of Dogs Teach Us About Human Emotions?, Dean Mobbs

Animal Sentience

It has long been believed that social emotions such as guilt and jealousy are only expressed in humans. In the case of jealousy, its adaptive value has been linked to the prevention of sexual infidelity or fairness. So why would dogs feel jealousy? I suggest that understanding how social emotions have been bred into dogs can help us understand our own emotions, including their functionality — and potentially their mechanisms.

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Can Neuroimaging In Dogs Have Practical Implications?, Tiffani J. Howell Jan 2018

Can Neuroimaging In Dogs Have Practical Implications?, Tiffani J. Howell

Animal Sentience

Jealousy, or at least aggression, can be observed in dogs using neuroimaging techniques, but this response attenuates quickly following repeated exposure to the aggression-inducing stimulus. This may have a practical application. Early socialisation as a puppy, and habituation as an adult dog, could help prevent undesirable behaviours such as predatory behaviour. It is unclear whether these processes are the same, and affected only by the dog’s age. Neuroimaging could help us understand whether the same neurological processes underlie socialisation and habituation, and whether self-rewarding behaviours such as predatory behaviour could be stopped using socialisation/habituation techniques.

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Lessons From Behaviour For Brain Imaging, Carolyn J. Walsh Jan 2018

Lessons From Behaviour For Brain Imaging, Carolyn J. Walsh

Animal Sentience

Integrating physiological and behavioural arousal with social context is fundamental to understanding affect in dogs. Cook et al. (2018) have made a worthy start towards illuminating the neural basis of dog affect underlying resource loss. However, their study depends on retrospective behaviour reports versus direct testing, and an interpretation of differential neural activation that is based on too few dogs. Research groups conducting canine brain-imaging work might: (1) consider collaborative approaches to augment sample sizes and replicability, and (2) take a recent lesson from dog behavioural research regarding a more cautious approach to applying functional labels to physiological and/or behavioural …

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On Jealousy, Envy, Sex Differences And Temperament In Humans And Dogs, Eddie Harmon-Jones, Sylvia K. Harmon-Jones Jan 2018

On Jealousy, Envy, Sex Differences And Temperament In Humans And Dogs, Eddie Harmon-Jones, Sylvia K. Harmon-Jones

Animal Sentience

Cook, Prichard, Spivak, and Berns (2018) find that dogs’ levels of trait aggression are positively correlated with their amygdala activation when observing their caregivers giving a food to a fake dog. The authors conclude that this may provide neural evidence in dogs for the experience of jealousy, an emotion that some psychologists consider to be unique to humans. Here we explain the difference between the emotions of jealousy and envy, suggesting some ideas for future experiments that may help disentangle the experience of jealousy from that of envy in dogs. We also propose ideas for future research that may yield …

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Inferring Emotion From Amygdala Activation Alone Is Problematic, Thomas F. Denson Jan 2018

Inferring Emotion From Amygdala Activation Alone Is Problematic, Thomas F. Denson

Animal Sentience

Cook et al. investigated neural responses in domestic dogs in an experiment designed to elicit jealousy. Relative to a control condition, watching the dogs’ caregivers feed a fake dog activated the amygdala bilaterally. Dogs rated higher in dog-directed aggressiveness showed larger initial amygdala activation. Amygdala activity in this context is insufficient evidence to infer that the dogs experienced jealousy or even negative affect. The experimental design does not provide an adequate level of control to infer the presence of jealousy.

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Limits Of Neuroscience, Paul Morris Jan 2018

Limits Of Neuroscience, Paul Morris

Animal Sentience

Examining the relationship between jealous behaviour and the amygdala may be quite informative about the function of the amygdala, but the amygdala may be less helpful in informing us about jealous behaviour. Claims about the potential practical relevance of the results also require that the magnitude of the effects inform the relevant discussion. The dogs used in the study probably share some very important personality characteristics; this too limits the practical implications of Cook et al.’s findings for dogs in general. It is nevertheless a testament to the skill of the experimenters, and the amazing bond between dogs and humans, …

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Jealousy? Or Just Hostility Toward Other Dogs? The Risks Of Jumping To Conclusions, James A. Serpell Jan 2018

Jealousy? Or Just Hostility Toward Other Dogs? The Risks Of Jumping To Conclusions, James A. Serpell

Animal Sentience

Cook et al. (2018) provide a fascinating demonstration of amygdala activation in dogs when they witnessed their owners giving food to another (fake) dog, but not when they placed food in a bucket. Dogs’ neurological responses were positively correlated with their reported levels of ‘dog-directed aggression’ as measured by the C-BARQ, and dogs with initially strong amygdala responses habituated on subsequent trials. The authors interpret their findings as possible evidence for an emotion akin to jealousy in dogs. However, alternate interpretations involving either dog aggression/fear or emotional responses to food seem more plausible and avoid the welfare risks associated with …

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What Would We Like To Know By Imaging The Brains Of Dogs?, Ralph Adolphs Jan 2018

What Would We Like To Know By Imaging The Brains Of Dogs?, Ralph Adolphs

Animal Sentience

Using fMRI to study emotions in animals is important, fascinating, and fraught with methodological and conceptual problems. Cook et al. are doing it, and there is no question that they and others will be doing it better and better as time goes on. Where will this lead us? What could fMRI in principle tell us about the minds of nonhuman animals?

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What Is It Like To Be A Jealous Dog?, Emanuela Prato Previde, Paola Valsecchi Jan 2018

What Is It Like To Be A Jealous Dog?, Emanuela Prato Previde, Paola Valsecchi

Animal Sentience

Jealousy is a good candidate for comparative studies due to its clear adaptive value in protecting social bonds and affective relationships. Dogs are suitable subjects for investigating the evolution of jealousy, thanks to their rather sophisticated socio-cognitive abilities — which in some cases parallel those reported for human infants — and thanks to their long-lasting relationship with humans. The work of Cook and colleagues (2018) addresses the issue of jealousy in dogs through the lens of neuroscience, examining the relationship between the amygdala and jealousy. Their experiment has a number of methodological flaws that prevent distinguishing jealousy from other internal …

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