Domestication constrains the ability of dogs to convey emotions via facial expressions in comparison to their wolf ancestors

Dogs (Canis lupus familiaris) are the domestically bred descendant of wolves (Canis lupus). However, selective breeding has profoundly altered facial morphologies of dogs compared to their wolf ancestors. We demonstrate that these morphological differences limit the abilities of dogs to successfully produce the same affective facial expressions as wolves. We decoded facial movements of captive wolves during social interactions involving nine separate affective states. We used linear discriminant analyses to predict affective states based on combinations of facial movements. The resulting confusion matrix demonstrates that specific combinations of facial movements predict nine distinct affective states in wolves; the first assessment of this many affective facial expressions in wolves. However, comparative analyses with kennelled rescue dogs revealed reduced ability to predict affective states. Critically, there was a very low predictive power for specific affective states, with confusion occurring between negative and positive states, such as Friendly and Fear. We show that the varying facial morphologies of dogs (specifically non-wolf-like morphologies) limit their ability to produce the same range of affective facial expressions as wolves. Confusion among positive and negative states could be detrimental to human–dog interactions, although our analyses also suggest dogs likely use vocalisations to compensate for limitations in facial communication

Assessing the utility and limitations of accelerometers and machine learning approaches in classifying behaviour during lactation in a phocid seal

Background Classifying behaviour with animal-borne accelerometers is quickly becoming a popular tool for remotely observing behavioural states in a variety of species. Most accelerometry work in pinnipeds has focused on classifying behaviour at sea often quantifying behavioural trade-offs associated with foraging and diving in income breeders. Very little work to date has been done to resolve behaviour during the critical period of lactation in a capital breeder. Capital breeding phocids possess finite reserves that they must allocate appropriately to maintain themselves and their new offspring during their brief nursing period. Within this short time, fine-scale behavioural trade-offs can have significant fitness consequences for mother and offspring and must be carefully managed. Here, we present a case study in extracting and classifying lactation behaviours in a wild, breeding pinniped, the grey seal (Halichoerus grypus). Results Using random forest models, we were able to resolve 4 behavioural states that constitute the majority of a female grey seals’ activity budget during lactation. Resting, alert, nursing, and a form of pup interaction were extracted and classified reliably. For the first time, we quantified the potential confounding variance associated with individual differences in a wild context as well as differences due to sampling location in a largely inactive model species. Conclusions At this stage, the majority of a female grey seal’s activity budget was classified well using accelerometers, but some rare and context-dependent behaviours were not well captured. While we did find significant variation between individuals in behavioural mechanics, individuals did not differ significantly within themselves; inter-individual variability should be an important consideration in future efforts. These methods can be extended to other efforts to study grey seals and other pinnipeds who exhibit a capital breeding system. Using accelerometers to classify behaviour during lactation allows for fine-scale assessments of time and energy trade-offs for species with fixed stores

Magnetron Development

Contains reports on two research projects

Reactive stress-coping styles show more variable reproductive expenditure and fitness outcomes

Stress-coping styles dictate how individuals react to stimuli and can be measured by the integrative physiological parameter of resting heart-rate variability (HRV); low resting HRV indicating proactive coping styles, while high resting HRV typifies reactive individuals. Over 5 successive breeding seasons we measured resting HRV of 57 lactating grey seals. Mothers showed consistent individual differences in resting HRV across years. We asked whether proactive and reactive mothers differed in their patterns of maternal expenditure and short-term fitness outcomes within seasons, using maternal daily mass loss rate to indicate expenditure, and pup daily mass gain to indicate within season fitness outcomes. We found no difference in average rates of maternal daily mass loss or pup daily mass gain between proactive and reactive mothers. However, reactive mothers deviated more from the sample mean for maternal daily mass and pup daily mass gain than proactive mothers. Thus, while proactive mothers exhibit average expenditure strategies with average outcomes, expenditure varies much more among reactive mothers with more variable outcomes. Overall, however, mean fitness was equal across coping styles, providing a mechanism for maintaining coping style diversity within populations. Variability in reactive mothers’ expenditures and success is likely a product of their attempts to match phenotype to prevailing environmental conditions, achieved with varying degrees of success

The difference between night and day: The nocturnal and diurnal activity budget of gray seals (Halichoerus grypus) during the breeding season

PostprintPeer reviewe

Magnetron Development

Contains reports on three research projects

Seismogenic deformation field in the Mojave block and implications for tectonics of the eastern California shear zone

From the aftershocks of the 1992 Landers earthquake, we infer the orientation of the principal strain rate axes (d_1 > d_2 > d_3; d_1 lengthening), their relative magnitude, and the relative spin of fault blocks by using a micropolar continuum model to invert the seismic P and T axes. The seismogenic deformation is consistent with the geodetic measurements of the coseismic displacement and with the secular deformation of the central Mojave block. Regionally, the aftershock data define two major domains within the central Mojave block: (1) the western Mojave block, including the San Bernardino Mountains and the epicentral area of the Big Bear earthquake, which is characterized by E-W d_1 (lengthening) and N-S d_3 (shortening); and (2) the central Mojave block, including the Landers surface rupture zone, which is characterized by NW-SE d_1 and NE-SW d_3. Inversion for the principal strain axes of geodetically measured coseismic displacements across the Big Bear and Landers seismogenic zones gives results similar to the aftershock inversions for those areas, indicating that the aftershocks accommodate a deformation similar to the main rupture and do not reflect elastic rebound or residual stresses. The background seismicity for 1981 to 1991 shows the same characteristic d_1 and d_3 orientations for the two domains, indicating that the secular seismogenic strain has the same regional geometry as the 1992 coseismic deformation. The micropolar inversion also provides values of the relative vorticity parameter W, which reflects a difference between the vorticity of a shearing continuum and the vorticity of fault-bounded blocks rotating within tabular seismogenic shear zones. The observed fault geometry along the Kickapoo fault suggests a pinned-block model for the local block rotation that is consistent with the values of W obtained from our inversions. We interpret the regional NW-SE orientation of d_1 in the central Mojave block to be characteristic of the dextral eastern California shear zone, which transfers approximately 22% of the Pacific-North American plate motion from the San Andreas system to the Walker Lane Belt in eastern California. Our results and geodetic determinations of the secular shear strain in the central Mojave block indicate that the locus of NW dextral shear generally lies between the San Bernardino Mountains and the Pisgah fault

Seasonal changes in microbial community structure and activity imply winter production is linked to summer hypoxia in a large lake

Carbon and nutrient cycles in large temperate lakes such as Lake Erie are primarily driven by phototrophic and heterotrophic microorganisms, although our understanding of these is often constrained to late spring through summer due to logistical constraints. During periods of \u3e 90% ice cover in February of 2008, 2009, and 2010, we collected samples from an icebreaker for an examination of bacterial production as well as microbial community structure. In comparison with summer months (August 2002 and 2010), we tested hypotheses concerning seasonal changes in microbial community diversity and production. Bacterial production estimates were c. 2 orders of magnitude higher (volume normalized) in summer relative to winter. Our observations further demonstrate that the microbial community, including single-celled phototrophs, varied in composition between August and February. Sediment traps deployed and collected over a 3 year period (2008-2011) confirmed that carbon export was ongoing and not limiting winter production. The results support the notion that active primary producers in winter months export carbon to the sediments that is not consumed until the warmer seasons. The establishment of this linkage is a critical observation in efforts to understand the extent and severity of annual summertime formations of a zone of regional hypoxia in Lake Erie. Seasonal changes in microbial community productivity and diversity suggest primary production in winter months may exacerbate summer hypoxia in Lake Eri. © 2014 Federation of European Microbiological Societies