Man's underground best friend: domestic ferrets, unlike the wild forms, show evidence of dog-like social-cognitive skills

Meeting Ferret Enrichment Needs in Infectious Disease Laboratory Settings

Environmental enrichment is a necessary component of all research vivarium settings. However, appropriate enrichment decisions vary greatly depending on the species involved and the research use of the animals. The increasing use of ferrets in research settings-notably for modeling the pathogenicity and transmissibility of viral pathogens that require containment in ABSL-2 to -4 environments-presents a particular challenge for veterinary and research staff to ensure that enrichment needs for these animals are met consistently. Here, we discuss the species-specific enrichment needs of ferrets, enrichment considerations for ferrets housed in research settings, and the challenges and importance of providing appropriate enrichment during experimentation, including when ferrets are housed in high-containment facilities. This article is organized to support the easy availability of information that will facilitate the design and implementation of optimal environmental enrichment for ferrets used in diverse research efforts in vivarium settings.

Domestication and breeding objective did not shape the interpretation of physical and social cues in goats (Capra hircus)

Artificial selection by humans, either through domestication or subsequent selection for specific breeding objectives, drives changes in animal cognition and behaviour. However, most previous cognitive research comparing domestic and wild animals has focused on companion animals such as canids, limiting any general claims about the effects of artificial selection by humans. Using a cognitive test battery, we investigated the ability of wild goats (non-domestic, seven subjects), dwarf goats (domestic, not selected for milk production, 15 subjects) and dairy goats (domestic, selected for high milk yield, 18 subjects) to utilise physical and social cues in an object choice task. To increase the heterogeneity of our test samples, data for domestic goats were collected by two experimenters at two research stations (Agroscope; Research Institute for Farm Animal Biology). We did not find performance differences between the three groups in the cognitive test battery for either physical or social cues. This indicates that for a domestic non-companion animal species, domestication and selection for certain breeding objectives did not measurably shape the physical and cognitive skills of goats.

Are domesticated animals dumber than their wild relatives? A comprehensive review on the domestication effects on animal cognitive performance

Animal domestication leads to diverse behavioral, physiological, and neurocognitive changes in domesticated species compared to their wild relatives. However, the widely held belief that domesticated species are inherently less "intelligent" (i.e., have lower cognitive performance) than their wild counterparts requires further investigation. To investigate potential cognitive disparities, we undertook a thorough review of 88 studies comparing the cognitive performance of domesticated and wild animals. Approximately 30% of these studies showed superior cognitive abilities in wild animals, while another 30% highlighted superior cognitive abilities in domesticated animals. The remaining 40% of studies found similar cognitive performance between the two groups. Therefore, the question regarding the presumed intelligence of wild animals and the diminished cognitive ability of domesticated animals remains unresolved. We discuss important factors/limitations for interpreting past and future research, including environmental influences, diverse objectives of domestication (such as breed development), developmental windows, and methodological issues impacting cognitive comparisons. Rather than perceiving these limitations as constraints, future researchers should embrace them as opportunities to expand our understanding of the complex relationship between domestication and animal cognition.

Following the human point: Research with nonhuman animals since Povinelli, Nelson, and Boysen (1990)

For this special issue in honor of Dr. Sarah (Sally) Boysen's career, we review studies on point following in nonhuman animals. Of the 126 papers that we documented on this topic published since the publication of Povinelli, Nelson, and Boysen (1990, Journal of Comparative Psychology, 104, 203-210), 94 (75%) were published in the past 15 years, including 22 in the past 5 years, indicating that this topic is still an active area of interest in the field of animal behavior and cognition. We present results of a survey of publication trends, discussing the species tested and the sample sizes, and we note methodological considerations and current multilaboratory approaches. We then categorize and synthesize the research questions addressed in these studies, which have been at both the ultimate level (e.g., questions related to evolutionary adaptiveness and phylogenetic differences) and proximate level (e.g., questions related to experiential and temperamental processes). Throughout, we consider future directions for this area of research.

Intranasal Oxytocin Improves Social Behavior in Laboratory Beagle Dogs (Canis familiaris) Using a Custom-Made Social Test Battery

For a long time, oxytocin has been thought to have a generally positive effect on social cognition and prosocial behavior; however, recent results suggested that oxytocin has beneficial effects only under certain conditions. The aim of the present study was to explore potential associations between social competence and the effect of intranasal oxytocin on the social behavior of laboratory beagle dogs. We expected oxytocin treatment to have a more pronounced positive effect on dogs with lower baseline performance in a social test battery. Thirty-six adult dogs of both sexes received 32 IU intranasal oxytocin and physiological saline (placebo) treatment in a double-blind, cross-over design, with 17–20 days between the two sessions. Forty minutes after the treatment, dogs participated in a social test battery consisting of eight situations. The situations were carried out within one session and took 20–30 min to complete. Principal component analysis on the coded behaviors identified four components (Willingness to interact, Preference for social contact, Non-aversive response to nonsocial threat, and Non-aversive response to social threat). The subjects' behavior during the placebo condition was used to assess their baseline performance. We found that oxytocin treatment had a differential effect on the behavior depending on the baseline performance of the individuals in all components, but only two treatment × baseline performance interactions remained significant in a less sensitive analysis. In accordance with our hypothesis, oxytocin administration increased dogs' contact seeking and affiliative behaviors toward humans but only for those with low baseline performance. Dogs with low baseline performance also showed significantly more positive (friendly) reactions to social threat after oxytocin administration than after placebo, while for dogs with high baseline performance, oxytocin administration led to a more negative (fearful) reaction. These results indicate that similar to those on humans, the effects of oxytocin on dogs' social behavior are not universally positive but are constrained by individual characteristics and the context. Nevertheless, oxytocin administration has the potential to improve the social behavior of laboratory beagle dogs that are socially less proficient when interacting with humans, which could have both applied and animal welfare implications.

Training the domestic ferret to discriminate odors associated with wildlife disease

Recent avian influenza infection outbreaks have resulted in global biosecurity and economic concerns. Mallards are asymptomatic for the disease and can potentially spread AI along migratory bird flyways. In a previous study, trained mice correctly discriminated the health status of individual ducks on the basis of fecal odors when feces from post-infection periods were paired with feces from pre-infection periods. Chemical analyses indicated that avian influenza infection was associated with a marked increase of acetoin (3-hydroxy-2-butanone) in feces. In the current study, domesticated male ferrets (Mustela putorius furo) were trained to display a specific conditioned response (i.e. active scratch alert) in response to a marked increase of acetoin in a presentation of an acetoin:1-octen-3-ol solution. Ferrets rapidly generalized this learned response to the odor of irradiated feces from avian influenza infected mallards. These results suggest that a trained mammalian biosensor could be employed in an avian influenza surveillance program.

Did Dog Domestication Contribute to Language Evolution?

Different factors seemingly account for the emergence of present-day languages in our species. Human self-domestication has been recently invoked as one important force favoring language complexity mostly via a cultural mechanism. Because our self-domestication ultimately resulted from selection for less aggressive behavior and increased prosocial behavior, any evolutionary or cultural change impacting on aggression levels is expected to have fostered this process. Here, we hypothesize about a parallel domestication of humans and dogs, and more specifically, about a positive effect of our interaction with dogs on human self-domestication, and ultimately, on aspects of language evolution, through the mechanisms involved in the control of aggression. We review evidence of diverse sort (ethological mostly, but also archeological, genetic, and physiological) supporting such an effect and propose some ways of testing our hypothesis.

Cognition and the human-animal relationship: a review of the sociocognitive skills of domestic mammals toward humans

In the past 20 years, research focusing on interspecific sociocognitive abilities of animals toward humans has been growing, allowing a better understanding of the interactions between humans and animals. This review focuses on five sociocognitive abilities of domestic mammals in relation to humans as follows: discriminating and recognizing individual humans; perceiving human emotions; interpreting our attentional states and goals; using referential communication (perceiving human signals or sending signals to humans); and engaging in social learning with humans (e.g., local enhancement, demonstration and social referencing). We focused on different species of domestic mammals for which literature on the subject is available, namely, cats, cattle, dogs, ferrets, goats, horses, pigs, and sheep. The results show that some species have remarkable abilities to recognize us or to detect and interpret the emotions or signals sent by humans. For example, sheep and horses can recognize the face of their keeper in photographs, dogs can react to our smells of fear, and pigs can follow our pointing gestures. Nevertheless, the studies are unequally distributed across species: there are many studies in animals that live closely with humans, such as dogs, but little is known about livestock animals, such as cattle and pigs. However, on the basis of existing data, no obvious links have emerged between the cognitive abilities of animals toward humans and their ecological characteristics or the history and reasons for their domestication. This review encourages continuing and expanding this type of research to more abilities and species.

Cooperative Communication with Humans Evolved to Emerge Early in Domestic Dogs

Although we know that dogs evolved from wolves, it remains unclear how domestication affected dog cognition. One hypothesis suggests dog domestication altered social maturation by a process of selecting for an attraction to humans.^1-3 Under this account, dogs became more flexible in using inherited skills to cooperatively communicate with a new social partner that was previously feared and expressed these unusual social skills early in development.^4-6 Here, we comparedog (n = 44) and wolf (n = 37) puppies, 5-18 weeks old, on a battery of temperament and cognition tasks. We find that dog puppies are more attracted to humans, read human gestures more skillfully, and make more eye contact with humans than wolf puppies. The two species are similarly attracted to familiar objects and perform similarly on non-social measures of memory and inhibitory control. These results are consistent with the idea that domestication enhanced the cooperative-communicative abilities of dogs as selection for attraction to humans altered social maturation.

Human Self-Domestication and the Evolution of Pragmatics

As proposed for the emergence of modern languages, we argue that modern uses of languages (pragmatics) also evolved gradually in our species under the effects of human self-domestication, with three key aspects involved in a complex feedback loop: (a) a reduction in reactive aggression, (b) the sophistication of language structure (with emerging grammars initially facilitating the transition from physical aggression to verbal aggression); and (c) the potentiation of pragmatic principles governing conversation, including, but not limited to, turn-taking and inferential abilities. Our core hypothesis is that the reduction in reactive aggression, one of the key factors in self-domestication processes, enabled us to fully exploit our cognitive and interactional potential as applied to linguistic exchanges, and ultimately to evolve a specific form of communication governed by persuasive reciprocity-a trait of human conversation characterized by both competition and cooperation. In turn, both early crude forms of language, well suited for verbal aggression/insult, and later more sophisticated forms of language, well suited for persuasive reciprocity, significantly contributed to the resolution and reduction of (physical) aggression, thus having a return effect on the self-domestication processes. Supporting evidence for our proposal, as well as grounds for further testing, comes mainly from the consideration of cognitive disorders, which typically simultaneously present abnormal features of self-domestication (including aggressive behavior) and problems with pragmatics and social functioning. While various approaches to language evolution typically reduce it to a single factor, our approach considers language evolution as a multifactorial process, with each player acting upon the other, engaging in an intense mutually reinforcing feedback loop. Moreover, we see language evolution as a gradual process, continuous with the pre-linguistic cognitive abilities, which were engaged in a positive feedback loop with linguistic innovations, and where gene-culture co-evolution and cultural niche construction were the main driving forces.

An initial exploration of mirror behaviour in the ferret, Mustela putorius furo

Responses to mirrors vary in non-human animals. Many species respond socially to mirrors with relatively few species demonstrating self-recognition in mirrors. In this study, we investigated the responses of ferrets to mirrors. Six adult ferrets (3 males, 3 females, all over a year old) were exposed to mirrors and their responses were investigated over three experimental conditions (baseline, mirror preference, mark test) in a repeated measures design. Upon initial presentation, the ferrets showed more approach and sniffing behaviour toward the mirror than the non-reflective surface. The ferrets also showed a preference for the mirror and spent more time in close proximity to the mirror than the non-reflective surface. In the mirror mark test, the ferrets showed more approach, sniffing and self-exploration behaviour when they were marked and presented with the mirror compared to when they were marked and presented with the non-reflective surface, or when they were sham-marked and presented with either surface. Our findings are suggestive that ferrets show interest in mirrors and that further study exploring the responses of ferrets to mirrors is warranted.

Biodetection of a specific odor signature in mallard feces associated with infection by low pathogenic avian influenza A virus

Outbreaks of avian influenza virus (AIV) infection included the spread of highly pathogenic AIV in commercial poultry and backyard flocks in the spring of 2015. This resulted in estimated losses of more than $8.5 million from federal government expenditures, $1.6 billion from direct losses to produces arising from destroyed turkey and chicken egg production, and economy-wide indirect costs of $3.3 billion from impacts on retailers and the food service industries. Additionally, these outbreaks resulted in the death or depopulation of nearly 50 million domestic birds. Domesticated male ferrets (Mustela putorius furo) were trained to display a specific conditioned behavior (i.e. active scratch alert) in response to feces from AIV-infected mallards in comparison to feces from healthy ducks. In order to establish that ferrets were identifying samples based on odors associated with infection, additional experiments controlled for potentially confounding effects, such as: individual duck identity, housing and feed, inoculation concentration, and day of sample collection (post-infection). A final experiment revealed that trained ferrets could detect AIV infection status even in the presence of samples from mallards inoculated with Newcastle disease virus or infectious laryngotracheitis virus. These results indicate that mammalian biodetectors are capable of discriminating the specific odors emitted from the feces of non-infected versus AIV infected mallards, suggesting that the health status of waterfowl can be evaluated non-invasively for AIV infection via monitoring of volatile fecal metabolites. Furthermore, in situ monitoring using trained biodetectors may be an effective tool for assessing population health.

Is cognition the secret to working dog success?

Dogs' special relationship with humans not only makes them ubiquitous in our lives, but working dogs specifically perform essential functions for us such as sniffing out bombs and pulling wheelchairs for the disabled. To enhance the performance of working dogs, it is essential to understand the cognitive skills that underlie and lead to their success. This review details recent work in the field of canine cognition, including how dogs have evolved socio-cognitive skills that mimic or, in some cases, rival even our closest primate relatives. We review how these findings have laid the foundation for new studies that hope to help enhance working dog programs. This includes work that has begun to reveal the development and stability of the most important traits for service work. Discoveries like these suggest the possibility of translating what we have learned to improve breeding, selection, and training for these jobs. The latest research we review here shows promise in contributing to the production of better dogs and, consequently, more help for people.

What's in a Meow? A Study on Human Classification and Interpretation of Domestic Cat Vocalizations

Simple Summary

Cat–human communication is a core aspect of cat–human relationships and has an impact on domestic cats’ welfare. Meows are the most common human-directed vocalizations and are used in different everyday contexts to convey emotional states. This work investigates adult humans’ capacity to recognize meows emitted by cats during waiting for food, isolation, and brushing. We also assessed whether participants’ gender and level of empathy toward animals in general, and toward cats in particular, positively affect the recognition of cat meows. Participants were asked to complete an online questionnaire designed to assess their knowledge of cats and to evaluate their empathy toward animals. In addition, they listened to cat meows recorded in different situations and tried to identify the context in which they were emitted and their emotional valence. Overall, we found that, although meowing is mainly a human-directed vocalization and should represent a useful tool for cats to communicate emotional states to their owners, humans are not good at extracting precise information from cats’ vocalizations and show a limited capacity of discrimination based mainly on their experience with cats and influenced by gender and empathy toward them.

Abstract

Although the domestic cat (Felis catus) is probably the most widespread companion animal in the world and interacts in a complex and multifaceted way with humans, the human–cat relationship and reciprocal communication have received far less attention compared, for example, to the human–dog relationship. Only a limited number of studies have considered what people understand of cats’ human-directed vocal signals during daily cat–owner interactions. The aim of the current study was to investigate to what extent adult humans recognize cat vocalizations, namely meows, emitted in three different contexts: waiting for food, isolation, and brushing. A second aim was to evaluate whether the level of human empathy toward animals and cats and the participant’s gender would positively influence the recognition of cat vocalizations. Finally, some insights on which acoustic features are relevant for the main investigation are provided as a serendipitous result. Two hundred twenty-five adult participants were asked to complete an online questionnaire designed to assess their knowledge of cats and to evaluate their empathy toward animals (Animal Empathy Scale). In addition, participants had to listen to six cat meows recorded in three different contexts and specify the context in which they were emitted and their emotional valence. Less than half of the participants were able to associate cats’ vocalizations with the correct context in which they were emitted; the best recognized meow was that emitted while waiting for food. Female participants and cat owners showed a higher ability to correctly classify the vocalizations emitted by cats during brushing and isolation. A high level of empathy toward cats was significantly associated with a better recognition of meows emitted during isolation. Regarding the emotional valence of meows, it emerged that cat vocalizations emitted during isolation are perceived by people as the most negative, whereas those emitted during brushing are perceived as most positive. Overall, it emerged that, although meowing is mainly a human-directed vocalization and in principle represents a useful tool for cats to communicate emotional states to their owners, humans are not particularly able to extract precise information from cats’ vocalizations and show a limited capacity of discrimination based mainly on their experience with cats and influenced by empathy toward them.

The hippocampal formation of two carnivore species: The feliform banded mongoose and the caniform domestic ferret

Employing cyto-, myelo-, and chemoarchitectural staining techniques, we analyzed the structure of the hippocampal formation in the banded mongoose and domestic ferret, species belonging to the two carnivoran superfamilies, which have had independent evolutionary trajectories for the past 55 million years. Our observations indicate that, despite the time since sharing a last common ancestor, these species show extensive similarities. The four major portions of the hippocampal formation (cornu Ammonis, dentate gyrus, subicular complex, and entorhinal cortex) were readily observed, contained the same internal subdivisions, and maintained the topological relationships of these subdivisions that could be considered typically mammalian. In addition, adult hippocampal neurogenesis was observed in both species, occurring at a rate similar to that observed in other mammals. Despite the overall similarities, several differences to each other, and to other mammalian species, were observed. We could not find evidence for the presence of the CA2 and CA4 fields of the cornu Ammonis region. In the banded mongoose the dentate gyrus appears to be comprised of up to seven lamina, through the sublamination of the molecular and granule cell layers, which is not observed in the domestic ferret. In addition, numerous subtle variations in chemoarchitecture between the two species were observed. These differences may contribute to an overall variation in the functionality of the hippocampal formation between the species, and in comparison to other mammalian species. These similarities and variations are important to understanding to what extent phylogenetic affinities and constraints affect potential adaptive evolutionary plasticity of the hippocampal formation.

Maternal Immune Activation Alters Adult Behavior, Gut Microbiome and Juvenile Brain Oscillations in Ferrets

Maternal immune activation (MIA) has been identified as a causal factor in psychiatric disorders by epidemiological studies in humans and mechanistic studies in rodent models. Addressing this gap in species between mice and human will accelerate the understanding of the role of MIA in the etiology of psychiatric disorders. Here, we provide the first study of MIA in the ferret (Mustela putorius furo), an animal model with a rich history of developmental investigations due to the similarities in developmental programs and cortical organization with primates. We found that after MIA by injection of PolyIC in the pregnant mother animal, the adult offspring exhibited reduced social behavior, less eye contact with humans, decreased recognition memory, a sex-specific increase in amphetamine-induced hyperlocomotion, and altered gut microbiome. We also studied the neurophysiological properties of the MIA ferrets in development by in-vivo recordings of the local field potential (LFP) from visual cortex in five- to six-week-old animals, and found that the spontaneous and sensory-evoked LFP had decreased power, especially in the gamma frequency band. Overall, our results provide the first evidence for the detrimental effect of MIA in ferrets and support the use of the ferret as an intermediate model species for the study of disorders with neurodevelopmental origin.

Vegetative symptoms and behaviour of the therapy-accompanying dog of a chronically suicidal patient

We herein present a 51-year-old single female inpatient with treatment-resistant recurrent depressive disorder. Her most recent depressive episode has been severe and followed a chronic course, lasting for longer than 2 years. During the exacerbation of the patient's suicidal thoughts and plans, we repeatedly and independently observed vegetative and behavioural changes of the therapy-accompanying dog of the patient. Our findings suggest a role for dog-assisted therapy for augmenting treatment as well as for enhancing and developing novel adjunctive strategies for risk assessment in patients with chronic depression and suicidality. Possible social-biological mechanisms and underpinnings are discussed, by drawing on the available literature and comparative psychology. Collaboration with animal behaviourists and animal welfare scientists, in order to improve behavioural and physiological data interpretation and humaneness of dog-assisted therapy, is emphasised as a crucial component of future research.

Human Demonstration Does Not Facilitate the Performance of Horses (Equus caballus) in a Spatial Problem-Solving Task

Simple Summary

Horses were confronted with a spatial problem-solving task in which they had to detour an obstacle. Individuals that observed a human demonstrating how to solve the task did not solve the task more often or faster compared with a control group without demonstration. However, horses of both the treatment and control group detoured the obstacle faster over trials. Together with previous research, our results illustrate that horses do not seem to rely on social information when solving a spatial problem-solving task.

Abstract

Horses’ ability to adapt to new environments and to acquire new information plays an important role in handling and training. Social learning in particular would be very adaptive for horses as it enables them to flexibly adjust to new environments. In the context of horse handling, social learning from humans has been rarely investigated but could help to facilitate management practices. We assessed the impact of human demonstration on the spatial problem-solving abilities of horses during a detour task. In this task, a bucket with a food reward was placed behind a double-detour barrier and 16 horses were allocated to two test groups of 8 horses each. One group received a human demonstration of how to solve the spatial task while the other group received no demonstration. We found that horses did not solve the detour task more often or faster with human demonstration. However, both test groups improved rapidly over trials. Our results suggest that horses prefer to use individual rather than social information when solving a spatial problem-solving task.

Founder events, isolation, and inbreeding: Intercontinental genetic structure of the domestic ferret

Domestication and breeding for human-desired morphological traits can reduce population genetic diversity via founder events and artificial selection, resulting in inbreeding depression and genetic disorders. The ferret (Mustela putorius furo) was domesticated from European polecats (M. putorius), transported to multiple continents, and has been artificially selected for several traits. The ferret is now a common pet, a laboratory model organism, and feral ferrets can impact native biodiversity. We hypothesized global ferret trade resulted in distinct international genetic clusters and that ferrets transported to other continents would have lower genetic diversity than ferrets from Europe because of extreme founder events and no hybridization with wild polecats or genetically diverse ferrets. To assess these hypotheses, we genotyped 765 ferrets at 31 microsatellites from 11 countries among the continents of North America, Europe, and Australia and estimated population structure and genetic diversity. Fifteen M. putorius were genotyped for comparison. Our study indicated ferrets exhibit geographically distinct clusters and highlights the low genetic variation in certain countries. Australian and North American clusters have the lowest genetic diversities and highest inbreeding metrics whereas the United Kingdom (UK) cluster exhibited intermediate genetic diversity. Non-UK European ferrets had high genetic diversity, possibly a result of introgression with wild polecats. Notably, Hungarian ferrets had the highest genetic diversity and Hungary is the only country sampled with two wild polecat species. Our research has broad social, economic, and biomedical importance. Ferret owners and veterinarians should be made aware of potential inbreeding depression. Breeders in North America and Australia would benefit by incorporating genetically diverse ferrets from mainland Europe. Laboratories using ferrets as biomedical organisms should consider diversifying their genetic stock and incorporating genetic information into bioassays. These results also have forensic applications for conserving the genetics of wild polecat species and for identifying and managing sources of feral ferrets causing ecosystem damage.

Free-ranging dogs show age related plasticity in their ability to follow human pointing

Differences in pet dogs' and captive wolves' ability to follow human communicative intents have led to the proposition of several hypotheses regarding the possession and development of social cognitive skills in dogs. It is possible that the social cognitive abilities of pet dogs are induced by indirect conditioning through living with humans, and studying free-ranging dogs can provide deeper insights into differentiating between innate abilities and conditioning in dogs. Free-ranging dogs are mostly scavengers, indirectly depending on humans for their sustenance. Humans can act both as food providers and as threats to these dogs, and thus understanding human gestures can be a survival need for the free-ranging dogs. We tested the responsiveness of such dogs in urban areas toward simple human pointing cues using dynamic proximal points. Our experiment showed that pups readily follow proximal pointing and exhibit weaker avoidance to humans, but stop doing so at the later stages of development. While juveniles showed frequent and prolonged gaze alternations, only adults adjusted their behaviour based on the reliability of the human experimenter after being rewarded. Thus free-ranging dogs show a tendency to respond to human pointing gestures, with a certain level of behavioural plasticity that allows learning from ontogenic experience.

Endocrinopathy and Aging in Ferrets

Ferrets have become more popular as household pets and as animal models in biomedical research in the past 2 decades. The average life span of ferrets is about 5-11 years with onset of geriatric diseases between 3-4 years including endocrinopathies, neoplasia, gastrointestinal diseases, cardiomyopathy, splenomegaly, renal diseases, dental diseases, and cataract. Endocrinopathies are the most common noninfectious disease affecting middle-aged and older ferrets. Spontaneous neoplasms affecting the endocrine system of ferrets appear to be increasing in prevalence with a preponderance toward proliferative lesions in the adrenal cortex and pancreatic islet cells. Diet, gonadectomy, and genetics may predispose ferrets to an increased incidence of these endocrinopathies. These functional proliferative lesions cause hypersecretion of hormones that alter the physiology and metabolism of the affected ferrets resulting in a wide range of clinical manifestations. However, there is an apparent dearth of information available in the literature about the causal relationship between aging and neoplasia in ferrets. This review provides a comprehensive overview of the anatomy and physiology of endocrine organs, disease incidence, age at diagnosis, clinical signs, pathology, and molecular markers available for diagnosis of various endocrine disorders in ferrets.

Reward type and behavioural patterns predict dogs' success in a delay of gratification paradigm

Inhibiting an immediate behaviour in favour of an alternative but more advantageous behaviour has been linked to individual success in life, especially in humans. Dogs, which have been living in the human environment for thousands of years, are exposed to daily situations that require inhibition different in context from other non-domesticated species. One task regularly used to study inhibitory control is the delay of gratification task, which requires individuals to choose between an immediate option of lower value and a delayed option of higher value. We tested sixteen dogs in a non-social delay of gratification task, conducting two different conditions: a quality and a quantity condition. While the majority of dogs failed to wait for more than 10 s, some dogs tolerated delays of up to 140 s, while one dog waited for 15 minutes. Moreover, dogs had more difficulties to wait if the reward increased in terms of quantity than quality. Interestingly, dogs were able to anticipate the delay duration and some dogs developed behavioural patterns that predicted waiting, which seems similar in some respects to 'coping-strategies' found in children, chimpanzees and parrots. Our results indicate that strategies to cope with impulsivity seem to be consistent and present across animal taxa.

Unraveling the evolution of uniquely human cognition

A satisfactory account of human cognitive evolution will explain not only the psychological mechanisms that make our species unique, but also how, when, and why these traits evolved. To date, researchers have made substantial progress toward defining uniquely human aspects of cognition, but considerably less effort has been devoted to questions about the evolutionary processes through which these traits have arisen. In this article, I aim to link these complementary aims by synthesizing recent advances in our understanding of what makes human cognition unique, with theory and data regarding the processes of cognitive evolution. I review evidence that uniquely human cognition depends on synergism between both representational and motivational factors and is unlikely to be accounted for by changes to any singular cognitive system. I argue that, whereas no nonhuman animal possesses the full constellation of traits that define the human mind, homologies and analogies of critical aspects of human psychology can be found in diverse nonhuman taxa. I suggest that phylogenetic approaches to the study of animal cognition-which can address questions about the selective pressures and proximate mechanisms driving cognitive change-have the potential to yield important insights regarding the processes through which the human cognitive phenotype evolved.

Differential effects of oxytocin on social sensitivity in two distinct breeds of dogs (Canis familiaris)

Dogs have been proven to show several human-analogue social behaviors, and recent research raises the possibility that the oxytocin system is related to these. However, despite dogs' general tendency to excel in the domain of social cognition, there is increasing evidence that dogs' ability to utilize human signals may vary with breed. Moreover, breeds may show differences not only in their 'inborn' communicative abilities, but also in their learning skills related to these. The aim of the present study was to explore breed differences and breed-specific effects of oxytocin administration on different aspects of social responsiveness. Dogs from two markedly different breeds, Border Collies (cooperative workers) and Siberian Huskies (independent workers) were tested. After having received intranasal administration of oxytocin or placebo, subjects participated in three behavioral tests measuring social responsiveness. Our results show that there are several behavioral differences between the two breeds and also that there are differential effects of the oxytocin treatment. Border Collies were in general more susceptible to the 'social' effects of oxytocin compared to Siberian Huskies: after oxytocin administration they (1) looked more at the experimenter in the 'Unreachable food' situation, (2) looked more at the owner and shifted their gaze more between the sound source and the owner in a potentially dangerous situation, and (3) looked longer at the experimenter's eyes in the 'Tolerance of prolonged eye contact' test. These findings suggest that selection for enhanced cooperative abilities, possibly complemented by the effect of different social environments the two breeds experience, affects dogs' performance in several behavioral tests and that the neurohormonal background differently modulates social behavior in different working breeds.

Piglets Learn to Use Combined Human-Given Visual and Auditory Signals to Find a Hidden Reward in an Object Choice Task

Although animals rarely use only one sense to communicate, few studies have investigated the use of combinations of different signals between animals and humans. This study assessed for the first time the spontaneous reactions of piglets to human pointing gestures and voice in an object-choice task with a reward. Piglets (Sus scrofa domestica) mainly use auditory signals–individually or in combination with other signals—to communicate with their conspecifics. Their wide hearing range (42 Hz to 40.5 kHz) fits the range of human vocalisations (40 Hz to 1.5 kHz), which may induce sensitivity to the human voice. However, only their ability to use visual signals from humans, especially pointing gestures, has been assessed to date. The current study investigated the effects of signal type (visual, auditory and combined visual and auditory) and piglet experience on the piglets’ ability to locate a hidden food reward over successive tests. Piglets did not find the hidden reward at first presentation, regardless of the signal type given. However, they subsequently learned to use a combination of auditory and visual signals (human voice and static or dynamic pointing gestures) to successfully locate the reward in later tests. This learning process may result either from repeated presentations of the combination of static gestures and auditory signals over successive tests, or from transitioning from static to dynamic pointing gestures, again over successive tests. Furthermore, piglets increased their chance of locating the reward either if they did not go straight to a bowl after entering the test area or if they stared at the experimenter before visiting it. Piglets were not able to use the voice direction alone, indicating that a combination of signals (pointing and voice direction) is necessary. Improving our communication with animals requires adapting to their individual sensitivity to human-given signals.

2016 Guidelines of the American Society of Mammalogists for the use of wild mammals in research and education

Guidelines for use of wild mammal species in research are updated from Sikes et al. (2011) . These guidelines cover current professional techniques and regulations involving the use of mammals in research and teaching; they also incorporate new resources, procedural summaries, and reporting requirements. Included are details on capturing, marking, housing, and humanely killing wild mammals. It is recommended that Institutional Animal Care and Use Committees (IACUCs), regulatory agencies, and investigators use these guidelines as a resource for protocols involving wild mammals, whether studied in the field or in captivity. These guidelines were prepared and approved by the American Society of Mammalogists (ASM), in consultation with professional veterinarians experienced in wildlife research and IACUCs, whose collective expertise provides a broad and comprehensive understanding of the biology of nondomesticated mammals. The current version of these guidelines and any subsequent modifications are available online on the Animal Care and Use Committee page of the ASM website ( http://mammalogy.org/uploads/committee_files/CurrentGuidelines.pdf ). Additional resources pertaining to the use of wild animals in research are available at: http://www.mammalsociety.org/committees/animal-care-and-use#tab3 .

Increasing arousal enhances inhibitory control in calm but not excitable dogs

The emotional-reactivity hypothesis proposes that problem-solving abilities can be constrained by temperament, within and across species. One way to test this hypothesis is with the predictions of the Yerkes-Dodson law. The law posits that arousal level, a component of temperament, affects problem solving in an inverted U-shaped relationship: Optimal performance is reached at intermediate levels of arousal and impeded by high and low levels. Thus, a powerful test of the emotional-reactivity hypothesis is to compare cognitive performance in dog populations that have been bred and trained based in part on their arousal levels. We therefore compared a group of pet dogs to a group of assistance dogs bred and trained for low arousal (N = 106) on a task of inhibitory control involving a detour response. Consistent with the Yerkes-Dodson law, assistance dogs, which began the test with lower levels of baseline arousal, showed improvements when arousal was artificially increased. In contrast, pet dogs, which began the test with higher levels of baseline arousal, were negatively affected when their arousal was increased. Furthermore, the dogs' baseline levels of arousal, as measured in their rate of tail wagging, differed by population in the expected directions. Low-arousal assistance dogs showed the most inhibition in a detour task when humans eagerly encouraged them, while more highly aroused pet dogs performed worst on the same task with strong encouragement. Our findings support the hypothesis that selection on temperament can have important implications for cognitive performance.

Behavior genetics and the domestication of animals

Across species, a similar suite of traits tends to develop in response to domestication, including modifications in behavior. Reduced fear and increased stress tolerance were central in early domestication, and many domestication-related behaviors may have developed as traits correlated to reduced fear. Genetic mechanisms involved in domestication of behavior can be investigated by using top-down or bottom-up approaches, either starting from the behavior variation and searching for underlying genes or finding selected loci and then attempting to identify the associated phenotypes. Combinations of these approaches have proven powerful, and examples of results from such studies are presented and discussed. This includes loci associated with tameness in foxes and dogs, as well as loci correlated with reduced aggression and increased sociality in chickens. Finally, some examples are provided on epigenetic mechanisms in behavior, and it is suggested that selection of favorable epigenetic variants may have been an important mechanism in domestication.

Is the ferret a suitable species for studying perinatal brain injury?

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Ferret brain architecture, composition, and development are similar to humans.

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Postnatal ferret brain development is comparable to that of premature infants.

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Ferrets have potential to model preterm and term neonatal brain injury.

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Ferrets may fulfill the need for an intermediate model species of neurodevelopment.

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Many opportunities exist to expand the use of ferrets as research subjects.

Complications of prematurity often disrupt normal brain development and/or cause direct damage to the developing brain, resulting in poor neurodevelopmental outcomes. Physiologically relevant animal models of perinatal brain injury can advance our understanding of these influences and thereby provide opportunities to develop therapies and improve long-term outcomes. While there are advantages to currently available small animal models, there are also significant drawbacks that have limited translation of research findings to humans. Large animal models such as newborn pig, sheep and nonhuman primates have complex brain development more similar to humans, but these animals are expensive, and developmental testing of sheep and piglets is limited. Ferrets (Mustela putorius furo) are born lissencephalic and undergo postnatal cortical folding to form complex gyrencephalic brains. This review examines whether ferrets might provide a novel intermediate animal model of neonatal brain disease that has the benefit of a gyrified, altricial brain in a small animal. It summarizes attributes of ferret brain growth and development that make it an appealing animal in which to model perinatal brain injury. We postulate that because of their innate characteristics, ferrets have great potential in neonatal neurodevelopmental studies.

A comparison of pet and purpose-bred research dog (Canis familiaris) performance on human-guided object-choice tasks

Several studies have shown that domestic dogs respond to human social cues such as pointing. Some experiments have shown that pet dogs outperformed wolves in following a momentary distal point. These findings have lent support to the hypothesis that domestication is responsible for domestic dogs' ability to utilize human gestures. Other studies demonstrating comparable performance in human-socialized wolves suggest this skill depends on experience with relevant human stimuli. However, domestic dogs lacking thorough exposure to humans are underrepresented in the comparative literature. The goal of this study was to evaluate pet and kennel-reared research domestic dogs on their ability to follow two types of point in an object-choice task. This study used young adult, intact male research dogs (n=11) and a comparison group of pet dogs living in human homes (n=9). We found that while pet dogs followed the momentary distal point above chance levels, research dogs did not. Both groups followed the simpler dynamic proximal point; however, pet dogs outperformed research dogs on this task. Our results indicate that ontogenetic experiences may influence a domestic dog's ability to use human gestures, highlighting the importance of testing different sub-populations of domestic dogs.

Fetching what the owner prefers? Dogs recognize disgust and happiness in human behaviour

Research using the two-object choice paradigm showed that dogs prefer the object associated with the happy human emotion. However, they provided rather ambiguous results regarding the negative emotions. We assumed that differences between the dogs' and owners' interest towards the 'negative' object might be responsible for this. In our experiment, dogs observed their owner expressing different emotions towards two uniform plastic bottles. Five dog groups were tested based on the condition they received: (1) happy versus neutral, (2) happy versus disgust, (3) neutral versus disgust and (4-5) neutral vs neutral, as control groups. Contrary to previous studies using free choice paradigm, we used a task-driven approach. After the demonstration, the dogs had to retrieve one object to the owner. The dogs' performance in the two neutral-neutral groups did not differ from the chance level. In contrast, subjects were able to distinguish between the happy and neutral expression of the owner: they both approached and fetched the 'happy' object. In the happy-disgusted and neutral-disgusted groups, the dogs approached the bottles randomly, suggesting that they found the 'disgusting' and 'neutral' objects equally attractive. Nevertheless, the dogs preferentially retrieved the object marked with the relatively more positive emotion (happy or neutral) to the owner in both conditions. Our results demonstrate that dogs are able to recognize which is the more positive among two emotions, and in a fetching task situation, they override their own interest in the 'disgusting' object and retrieve what the owner prefers.

Dogs (Canis familiaris) account for body orientation but not visual barriers when responding to pointing gestures

In a series of four experiments we investigated whether dogs use information about a human's visual perspective when responding to pointing gestures. While there is evidence that dogs may know what humans can and cannot see, and that they flexibly use human communicative gestures, it is unknown if they can integrate these two skills. In Experiment 1 we first determined that dogs were capable of using basic information about a human's body orientation (indicative of her visual perspective) in a point following context. Subjects were familiarized with experimenters who either faced the dog and accurately indicated the location of hidden food, or faced away from the dog and (falsely) indicated the unbaited container. In test trials these cues were pitted against one another and dogs tended to follow the gesture from the individual who faced them while pointing. In Experiments 2-4 the experimenter pointed ambiguously toward two possible locations where food could be hidden. On test trials a visual barrier occluded the pointer's view of one container, while dogs could always see both containers. We predicted that if dogs could take the pointer's visual perspective they should search in the only container visible to the pointer. This hypothesis was supported only in Experiment 2. We conclude that while dogs are skilled both at following human gestures, and exploiting information about others' visual perspectives, they may not integrate these skills in the manner characteristic of human children.

Oxytocin receptor gene polymorphisms are associated with human directed social behavior in dogs (Canis familiaris)

The oxytocin system has a crucial role in human sociality; several results prove that polymorphisms of the oxytocin receptor gene are related to complex social behaviors in humans. Dogs' parallel evolution with humans and their adaptation to the human environment has made them a useful species to model human social interactions. Previous research indicates that dogs are eligible models for behavioral genetic research, as well. Based on these previous findings, our research investigated associations between human directed social behaviors and two newly described (-212AG, 19131AG) and one known (rs8679684) single nucleotide polymorphisms (SNPs) in the regulatory regions (5' and 3' UTR) of the oxytocin receptor gene in German Shepherd (N = 104) and Border Collie (N = 103) dogs. Dogs' behavior traits have been estimated in a newly developed test series consisting of five episodes: Greeting by a stranger, Separation from the owner, Problem solving, Threatening approach, Hiding of the owner. Buccal samples were collected and DNA was isolated using standard protocols. SNPs in the 3' and 5' UTR regions were analyzed by polymerase chain reaction based techniques followed by subsequent electrophoresis analysis. The gene-behavior association analysis suggests that oxytocin receptor gene polymorphisms have an impact in both breeds on (i) proximity seeking towards an unfamiliar person, as well as their owner, and on (ii) how friendly dogs behave towards strangers, although the mediating molecular regulatory mechanisms are yet unknown. Based on these results, we conclude that similarly to humans, the social behavior of dogs towards humans is influenced by the oxytocin system.

Juvenile domestic pigs (Sus scrofa domestica) use human-given cues in an object choice task

Research on the comprehension of human-given cues by domesticated as well as non-domesticated species has received considerable attention over the last decade. While several species seem to be capable of utilizing these cues, former work with domestic pigs (Sus scrofa domestica) has shown inconclusive results. In this study, we investigated the use of human-given cues in an object choice task by young domestic pigs (N = 17; 7 weeks of age) who had very limited human contact prior to the experiments. Subjects had to choose between two bowls of which only one was baited with a reward. Over the course of five experiments, pigs were able to use proximal and, with some constraints, also distal pointing cues presented in both a dynamic-sustained and in a momentary manner. When the experimenter was pointing from the incorrect bowl towards the correct one, most of the subjects had problems solving the task-indicating that some form of stimulus/local enhancement affected pigs' decision making. Interestingly, pigs were able to utilize the body and head orientation of a human experimenter to locate the hidden reward but failed to co-orient when head or body orientation of the experimenter was directed into distant space with no bowls present. Control trials ruled out the possibility that other factors (e.g. odour cues) affected subjects' choice behaviour. Learning during experiments played a minor role and only occurred in three out of twelve test conditions. We conclude that domestic pigs, even at a very young age, are skilful in utilizing various human-given cues in an object choice task-raising the question whether pigs only used stimulus/local enhancement and associative learning processes or whether they were able to comprehend the communicative nature of at least some of these cues.