At the end of the 1920s, Tanganyika Territory experienced several serious rodent outbreaks that threatened cotton and other grain production. At the same time, regular reports of pneumonic and bubonic plague occurred in the northern areas of Tanganyika. These events led the British colonial administration to dispatch several studies into rodent taxonomy and ecology in 1931 to determine the causes of rodent outbreaks and plague disease, and to control future outbreaks. The application of ecological frameworks to the control of rodent (...) outbreaks and plague disease transmission in colonial Tanganyika Territory gradually moved from a view that prioritised 'ecological interrelations' among rodents, fleas and people to one where those interrelations required studies into population dynamics, endemicity and social organisation in order to mitigate pests and pestilence. This shift in Tanganyika anticipated later population ecology approaches on the African continent. Drawing on sources from the Tanzania National Archives, this article offers an important case study of the application of ecological frameworks in a colonial setting that anticipated later global scientific interest in studies of rodent populations and rodent-borne disease ecologies. (shrink)

ABSTRACT In a series of experiments at the National Institute of Mental Health, the animal ecologist John B. Calhoun offered rats everything they needed, except space. The resulting population explosion was followed by a series of “social pathologies”—violence, sexual deviance, and withdrawal. This essay examines the influence of Calhoun's experiments among psychologists and sociologists concerned with the effects of the built environment on health and behavior. Some saw evidence of the danger of the crowd in Calhoun's “rat cities” and fastened (...) on a method of analysis that could be transferred to the study of urban man. Others, however, cautioned against drawing analogies between rodents and humans. The ensuing dispute saw social scientists involved in a careful negotiation over the structure and meaning of Calhoun's experimental systems and, with it, over the significance of the crowd in the laboratory, institution, and city. (shrink)

On top of working longer hours in paid employment and spending more time actively caring for children, parents, especially mothers, also feel pressured to safeguard the health of their children and the planet through their food consumption choices. Surprisingly, little evidence identifies whether the health value and environmental impact of food consumption choices impact judgments of parents’ abilities, morality, or general worth. We address this gap by drawing on an experiment administered to an online convenience sample of the United States (...) adult population. We find that the health value of a parent’s consumption choices only influences judgments of mothers, not fathers. Judgments of mothers and fathers are influenced by the environmental impact of their consumption choices. To add depth to these findings, we draw on supplementary interview data collected from 63 socioeconomically diverse residents of Washington State. The qualitative data demonstrate that people tend to ascribe the responsibility to make consumption choices to mothers, not fathers, and that participants value eco-friendly consumption because it represents a substantial commitment to a healthy lifestyle. These findings demonstrate that in the parenting context, consumption decisions influence social judgments and that food’s presumed health and environmental impact shape “feeding ideals” in gendered ways. Our evidence suggests the social costs for not meeting these ideals are more severe for mothers than for fathers. (shrink)

This article postulates a method of determining the date of human settlement in the Canary Islands by establishing when species of mice, which are commensal with human beings and hence in all likelihood migrated with them, arrived in the archipelago. At the same time, the extinction of several species of endemic rodents may also correlate with such arrivals. The study establishes the outer limits for the arrival of the mouse species, between the 5th millennium BCE and the 15th century (...) CE, but, while indicative archaeological evidence indicates human settlement was established by around the middle of the 1st millennium BCE, the absence of conclusive dating of fossil mice remains leaves a definitive conclusion for the start of such settlement still open. (shrink)

Contrary to the outstanding simplistic view of the taste system, learning studies show a more complex picture. Behavioral data using conditioned taste preference and aversion tasks support the idea that mixtures involve complex interactions between individual taste cues. Evidence from taste conditioned blocking, taste perceptual learning, and taste learned preferences is considered to support such a view. Greater support for research in taste learning and memory is required for a complete understanding of taste recognition.

In the quest to discover the neural bases of cognition, rigorous behavioral tools are equally as important as sophisticated tools for neural intervention. This paper evaluates several episodes in the development of a novel behavioral tool for rodent cognitive testing, the rodent touchscreen operant chamber. Using conceptual tools on offer in the philosophical literature on exploratory experimentation and control, I illuminate how optimization of this behavioral tool and an understanding of the causal knowledge it may be used to generate historically (...) has involved dynamic interplay between community-driven exploratory practices operating in parallel with causal hypothesis-driven research. (shrink)

Communication is inherent to social relationships. Previous papers addressed the correlation between social and communicative complexity, and the origin of sociality in rodents. In subterranean social species, as the number of animals in the same burrow increases, so do interindividual contact rates. This is because of limitations in actually used tunnel length and diameter, leading to an increasing number of agonistic situations probably resulting in time loss, threatening, and fighting with danger of injuries. To avoid this, social species are (...) expected to have an increase in the number of particular vocalizations. Comparison of the adult vocal repertoire of 12 species through regression and phylogenetically independent contrasts suggests three main conclusions: social species increase their repertoire both in number and categories of vocal signals in relation to solitary species, although the coefficient was smaller in the PIC model; the number of agonistic vocalizations was also different between solitary and social species, with the latter displaying higher numbers of these calls; the percentage of agonistic vocalizations in relation to total repertoire was similar between social and solitary species, with no significant relationship between this parameter and the social structure. These results imply that agonistic vocalizations have also increased in number in social species, indicating the importance of these calls in the establishment of new relationships. As repertoire changes are essential to cope with new and frequent kinds of interactions sociality originates, these results suggest that at least for these organisms, communicative changes, especially at the level of agonistic signals, could be a necessary condition to fulfill in the path to the possibility of group living. (shrink)

Using devices such as unified power quality conditioners in distribution networks seems essential for higher electricity quality. Moreover, distribution network reconfiguration is a suitable model for improving network characteristics, including loss reduction and voltage increase for distribution networks, and is widely used in this era. Here, the study discusses the rechanging of distribution networks for UPQC via proposing an appropriate model for it. In addition to the optimum structure of distribution networks, the most appropriate branch where UPQC must be located (...) and the most appropriate reactive power size with which series and shunt filters must be injected into the grid are determined. The simulations have been applied on two 69- and 84-standard-bus networks. The results of the simulations indicate much power loss reduction and much voltage increase in the presence of UPQC compensators. (shrink)

Head direction (HD) cells, abundant in the rat postsubiculum and anterior thalamic nuclei, fire maximally when the rat’s head is facing a particular direction. The activity of a population of these cells forms a distributed representation of the animal’s current heading. We describe a neural network model that creates a stable, distributed representation of head direction and updates that representation in response to angular velocity information. In contrast to earlier models, our model of the head direction system accurately tracks a (...) series of actual rat head rotations, and, using biologically plausible neurons, it fits the single-cell tuning curves of real HD cells recorded from rats executing those same rotations. The model makes neurophysiological predictions that can be tested using current technologies. (shrink)

Sex dimorphism occurs when group means differ by four or more standard deviations. However, the average size of the corpus callosum is greater in males by about one standard deviation in rats, 0.2 standard deviation in humans, and virtually zero in mice. Furthermore, variations in corpus callosum size are related to brain size and are not sex specific.

Phylogeography and zooarchaeology are largely separate disciplines, yet each interrogates relationships between humans and commensal species. Knowledge gained about human history from studies of four commensal rats (Rattus rattus, R. tanezumi, R. exulans, and R. norvegicus) is outlined, and open questions about their spread alongside humans are identified. Limitations of phylogeographic and zooarchaeological studies are highlighted, then how integration would increase understanding of species’ demographic histories and resultant inferences about human societies is discussed. How rat expansions have informed the understanding (...) of human migration, urban settlements, trade networks, and intra‐ and interspecific competition is reviewed. Since each rat species is associated with different human societies, they identify unique ecological and historical/cultural conditions that influenced their expansion. Finally, priority research areas including nuclear genome based phylogeographies are identified using archaeological evidence to understand R. norvegicus expansion across China, multi‐wave colonization of R. rattus across Europe, and competition between R. rattus and R. norvegicus. (shrink)