Biology subjects

Hansen Wheat, C.

Publications and source records attributed to Hansen Wheat, C..

5 recordsLinked to original sources

bioRxiv2025

Group size influences behavioral plasticity in responses to thermoregulation-foraging trade-offs by a socially cohesive bird

Behavioral plasticity, such as changes in habitat use and activity, can be a critical modulator of thermal pressures on endotherms. However, shifts in behaviors can meet diversified costs such as missed feeding opportunities. Individual decision-making should therefore capture the trade-off between the costs and the benefits of thermoregulation. In the case of social species, the decision process could also be facilitated or slowed down by the modulation of costs arising through the social environment. In this study, we tested how vulturine guineafowl (Acryllium vulturinum) change their use of open areas (where they predominately forage) according to heat using GPS data from 105 birds collected every 5 minutes for 6 months. Because animals vary in their sensitivity to risk according to group size--e.g. due to the dilution effect--we compared the responses of individuals depending on the size of the group they belong to. We also analyzed if behavioral responses translate into less precise thermoregulation by recording the body temperature of a subset of birds in two groups. We foundd that birds avoid heat by selectively using open areas and moving to cover, as well as reducing activity when temperature increases, birds use open areas less and move less. Individuals from intermediate-sized groups seemed to be able to use open areas during warmer conditions compared to individuals from small and large groups (10% higher probability of use). However, active birds in the open did not present hyperthermia, suggesting that behavioral changes are efficient or that individuals have other efficient strategies such as physiological cooling. Together, these results indicated that responses to high temperatures are complex, as they included not only a range of environmental constraints but that responses can also vary according to social context.

ecology↗

bioRxiv2020

Hand-reared wolves show similar, or stronger, attachment toward human caregivers compared to hand-reared dogs

Domesticated animals are generally assumed to display increased sociability towards humans compared to their wild ancestors. Dogs (Canis familiaris) have a remarkable ability to form social relationships with humans, including lasting attachment, a social bond based on emotional dependency. Since it has specifically been suggested that the ability to form attachment with humans evolved post-domestication in dogs, attempts to quantify attachment in wolves (Canis lupus), the ancestor of dogs, have subsequently been performed. However, while these rare wolf studies do highlight the potential for wolves to express attachment behaviour towards humans, the varied, and in some cases, contrasting results also emphasize the need for further testing of wolves. Here we used the standardized Strange Situation Test to investigate attachment behaviour expressed in wolves and dogs hand-reared and socialized under identical conditions. We found that 23 weeks old wolves and dogs equally discriminated between a stranger and a familiar person, and expressed similar attachment behaviours toward a familiar person. Additionally, wolves, but not dogs, expressed significantly elevated stress behaviour during the test, but this stress response was buffered by the presence of a familiar person. Wolves also expressed quantifiable fear responses to the stranger, whereas no such response was detectable in dogs. Together, our results suggest that wolves can show attachment toward humans comparable to that of dogs. Importantly, our findings demonstrate that the ability to form attachment with humans exists in relatives of the wild ancestor of dogs, thus refuting claims that such attachment is unique to post-domestication dog lineages.

animal behavior and cognition↗

bioRxiv2019

Intrinsically ball retrieving wolf puppies reveal standing ancestral variation for human-directed play behaviour

Domestication dramatically alters phenotypes. Standing variation among ancestral populations often drives phenotypic change during domestication, but some changes are caused by novel mutations. Dogs (Canis familiaris) engage in interspecific play with humans and it has specifically been suggested that the ability to interpret social-communicative behaviour expressed by humans is a novel dog-specific skill. Thus, wolves (Canis lupus) are not expected to engage in interspecific play with a human based on social-communicative cues. Here we report the observation of three eight week-old wolf puppies spontaneously responding to social-communicative behaviours from a stranger by retrieving a ball. This unexpected and novel observation has significant implications for our understanding and expectations of the genetic foundations of dog behaviour. Importantly, our observations indicate that behavioural responses to human social-communicative cues are not unique to dogs. This suggests that, while probably rare, standing variation in the expression of human-directed behaviour in ancestral populations could have been an important target for early selective pressures exerted during dog domestication.

evolutionary biology↗

bioRxiv2019

Dogs defy the domestication syndrome: morphology does not covary with predicted behavioural correlations within dog breeds

Domesticated animals display suites of altered morphological, behavioural and physiological traits compared to their wild ancestors, a phenomenon known as the domestication syndrome (DS). Because these alterations are observed to co-occur across a wide range of present day domesticates, the traits within the DS are assumed to covary within species and a single developmental mechanism has been hypothesized to cause the observed co-occurrence. However, due to the lack of formal testing it is currently not well-resolved if the traits within DS actually covary. Here we test the hypothesis that the presence of the classic morphological domestication traits white pigmentation, floppy ears and curly tails predict the strength of behavioural correlations in support of the DS in 78 dog breeds. Contrary to the expectations of covariation among DS traits, we found that morphological traits did not covary among themselves, nor did they predict the strength of behavioural correlations among dog breeds. Further, the number of morphological traits in a breed did not predict the strength of behavioural correlations. Our results thus contrast with the hypothesis that the DS arises due to a shared underlying mechanism, but more importantly, questions if the morphological traits embedded in the DS are actual domestication traits or post-domestication improvement traits. For dogs, it seems highly likely that strong selection for breed specific morphological traits only happened recently in relation to breed formation. Present day dogs therefore have limited bearing of the initial selection pressures applied during domestication and we should reevaluate our expectations of the DS accordingly.

evolutionary biology↗

bioRxiv2018

Dogs, but not wolves, lose their sensitivity towards novelty with age

Selection on behavioural traits holds a prominent role in the domestication of animals, with reductions in fear behaviour considered to be a key component. Specifically, there is a general assumption that domesticated species express reduced fear and reactivity towards novel stimuli compared to their ancestral species. However, very few studies have explicitly tested this proposed link between domestication and reduced fear responses. Of the limited number of studies experimentally addressing the alterations of fear during domestication, the majority have been done on canids. Previous work in foxes, wolves and dogs has led to the suggestion that decreased expression of fear in domesticated animals is linked to a domestication driven delay in the first onset of fearful behaviour during early ontogeny. Thus, wolves are expected to express exaggerated fearfulness earlier during ontogeny compared to dogs. However, while adult dogs are less fearful towards novelty than adult wolves and wolf-dog hybrids, consensus is lacking on when differences in fear expression arise in wolves and dogs. Here we present the first extended examination of fear development in hand-raised dogs and European grey wolves, using repeated novel object tests from six to 26 weeks of age. Contrary to expectations, we found no evidence in support of an increase in fearfulness in wolves with age or a delayed onset of fear response in dogs compared to wolves. Instead, we found that dogs strongly reduced their fear response in the period between six and 26 weeks of age, resulting in a significant species difference in fear expression towards novelty at 26 weeks. Critically, as wolves did not differ in their fear response towards novelty over time, the detected species difference was caused solely by a progressive reduced fear response in dogs. Our results thereby suggest that species differences in fear of novelty between wolves and dogs are not caused by a domestication driven shift in the first onset of fear response. Instead, we suggest that a loss of sensitivity towards novelty with age in dogs causes the difference in fear expression towards novelty in wolves and dogs.

animal behavior and cognition↗