Owner-assessed behaviours and relationships to gut microbiota composition in the domestic dog (Canis familiaris)

Behavioural issues in dogs, such as anxiety and aggression, are a prominent reason for both the relinquishment and euthanasia of pet dogs. These issues can cause a break-down of the dog-owner bond, and negatively impact quality of life for both dog and human. One potential area of research, the gut microbiome, provides the opportunity for better understanding the physiological process underlying the occurrence of aggression and anxiety, and recent studies have shown promise that changes in canine gut microbiota composition are associated with behaviour in dogs. However, a precise link between gut microbiota and behaviour has not yet been established in pet dogs, and previous studies have used clinical or shelter populations, rather than a community sample. I first highlight the demographic and lifestyle factors that may be related to the behaviour of dogs in this study, including the presence of conspecifics and the dog’s daily activities. In addition, I report on validity concerns for a subscale (familiar dog aggression) of a widely used, owner-reported dog behaviour survey, and present considerations for survey interpretation and improvement. Dogs cohabiting with other dogs in the same home, as well as singleton dogs whose owners unexpectedly completed questions about rivalry towards familiar (co-habiting) dogs, had different behavioural profiles compared to dogs living alone, whose owners did not respond to questions about dog rivalry. Finally, I investigate the links between the anxiety and aggression profiles and gut microbiota composition in dogs from the local area. Gut microbiota composition differed somewhat between dogs with higher and lower aggression scores, but most notably differed between those with differing anxiety scores, with the genus Blautia consistently associated with anxiety across multiple analyses. This thesis contributes to our growing understanding of gut microbiota composition in dogs with aggression or anxiety issues

Temperature-related differences in the calcium transient between Atlantic cod (Gadus morhua) and steelhead trout (Oncorhynchus mykiss) cardiomyocytes

The Atlantic cod, Gadus morhua, differs from many teleosts in that its heart does not respond to adrenergic stimulation, and is more capable of maintaining function during acute temperature changes. To examine if differences in intracellular calcium mobilization are associated with these atypical responses, confocal microscopy was used to study the calcium handling of cardiac cells from Atlantic cod vs. steelhead trout at their acclimation temperature (10ºC), or subjected to acute temperature changes (to 4 and 16ºC), while being stimulated across a range of frequencies (10 – 110 min⁻¹). In addition, cells were tested with and without tonic (10 nM) levels of adrenaline at 10ºC, and pharmacological blockers were used to study the relative contributions of the L-type Ca²⁺ channel, sarcoplasmic reticulum and Na+/Ca²⁺ exchanger to the Ca²⁺ transient. Consistent with previous in vitro and in situ studies, there were few significant effects of adrenaline on the Ca²⁺ transient of cod cardiomyocytes, yet adrenaline had significant positive inotropic effects on trout cardiomyocytes. At 10ºC, peak Ca²⁺ (F/F₀) only differed between the two species at low stimulation frequencies (10, 30 min-1), with trout F/F₀ 25-35% higher. In contrast, the time to peak Ca²⁺ and the time to half relaxation were both shorter (by 10 – 35% across frequencies) in cod. Acute temperature changes caused a shift in the Ca²⁺ - frequency relationship in both species, with F/F₀ values higher for trout at low frequencies (< 70 min⁻¹) at 4ºC, whereas this parameter was greater at all frequencies except 10 min⁻¹ in cod at 16ºC. Unfortunately, these experiments did not highlight clear species differences in the relative contributions of the L-type Ca²⁺ channels, sarcoplasmic reticulum and Na+/Ca²⁺ exchange to the Ca²⁺ transient

ManyDogs 1: A multi-lab replication study of dogs' pointing comprehension

To promote collaboration across canine science, address replicability issues, and advance open science practices within animal cognition, we have launched the ManyDogs consortium, modeled on similar ManyX projects in other fields. We aimed to create a collaborative network that (a) uses large, diverse samples to investigate and replicate findings, (b) promotes open science practices of pre-registering hypotheses, methods, and analysis plans, (c) investigates the influence of differences across populations and breeds, and (d) examines how different research methods and testing environments influence the robustness of results. Our first study combines a phenomenon that appears to be highly reliable—dogs’ ability to follow human pointing—with a question that remains controversial: do dogs interpret pointing as a social communicative gesture or as a simple associative cue? We collected data (N = 455) from 20 research sites on two conditions of a 2-alternative object choice task: (1) Ostensive (pointing to a baited cup after making eye-contact and saying the dog’s name); (2) Non-ostensive (pointing without eye-contact, after a throat-clearing auditory control cue). Comparing performance between conditions, while both were significantly above chance, there was no significant difference in dogs’ responses. This result was consistent across sites. Further, we found that dogs followed contralateral, momentary pointing at lower rates than has been reported in prior research, suggesting that there are limits to the robustness of point-following behavior: not all pointing styles are equally likely to elicit a response. Together, these findings underscore the important role of procedural details in study design and the broader need for replication studies in canine science

ManyDogs 1: A Multi-Lab Replication Study of Dogs’ Pointing Comprehension

To promote collaboration across canine science, address replicability issues, and advance open science practices within animal cognition, we have launched the ManyDogs consortium, modeled on similar ManyX projects in other fields. We aimed to create a collaborative network that (a) uses large, diverse samples to investigate and replicate findings, (b) promotes open science practices of pre-registering hypotheses, methods, and analysis plans, (c) investigates the influence of differences across populations and breeds, and (d) examines how different research methods and testing environments influence the robustness of results. Our first study combines a phenomenon that appears to be highly reliable—dogs’ ability to follow human pointing—with a question that remains controversial: do dogs interpret pointing as a social communicative gesture or as a simple associative cue? We collected data (N = 455) from 20 research sites on two conditions of a 2-alternative object choice task: (1) Ostensive (pointing to a baited cup after making eye-contact and saying the dog’s name); (2) Non-ostensive (pointing without eye-contact, after a throat-clearing auditory control cue). Comparing performance between conditions, while both were significantly above chance, there was no significant difference in dogs’ responses. This result was consistent across sites. Further, we found that dogs followed contralateral, momentary pointing at lower rates than has been reported in prior research, suggesting that there are limits to the robustness of point-following behavior: not all pointing styles are equally likely to elicit a response. Together, these findings underscore the important role of procedural details in study design and the broader need for replication studies in canine science