The diet of the dingo (Canis lupus dingo and hybrids) in north-eastern Australia: a supplement to the paper of Brook and Kutt (2011)

Dingoes and other wild dogs (Canis lupus dingo and hybrids) are generalist predators that consume a wide variety of different prey species within their range. Little is known, however, of the diets of dingoes in north-eastern Australia where the potential for impacts by dingoes exists. Recently new information has been provided on the diets of dingoes from several sites in Queensland, Australia, significantly adding to the body of published knowledge on ecosystems within this region. Further information on the diet of dingoes in north-eastern Australia is added from 1460 scats collected from five sites, representing tropical savannahs, tropical offshore islands (and a matched mainland area), dry sclerophyll forests and peri-urban areas on the fringe of Townsville. Macropods, possums and bandicoots were found to be common prey for dingoes in these areas. Evidence suggested that the frequency of prey remains in scats can be an unreliable indicator of predation risk to potential prey and it was found that novel and unexpected prey species appear in dingo diets as preferred prey become unavailable. The results support the generalisation that dingoes prefer medium- to large-sized native prey species when available but also highlight the capacity for dingoes to exploit populations of both large and small prey species that might not initially be considered at risk from predation based solely on data on scats.

Top predators as biodiversity regulators : the dingo Canis lupus dingo as a case study

Top-order predators often have positive effects on biological diversity owing to their key functional roles in regulating trophic cascades and other ecological processes. Their loss has been identified as a major factor contributing to the decline of biodiversity in both aquatic and terrestrial systems. Consequently, restoring and maintaining the ecological function of top predators is a critical global imperative. Here we review studies of the ecological effects of the dingo Canis lupus dingo, Australia's largest land predator, using this as a case study to explore the influence of a top predator on biodiversity at a continental scale. The dingo was introduced to Australia by people at least 3500 years ago and has an ambiguous status owing to its brief history on the continent, its adverse impacts on livestock production and its role as an ecosystem architect. A large body of research now indicates that dingoes regulate ecological cascades, particularly in arid Australia, and that the removal of dingoes results in an increase in the abundances and impacts of herbivores and invasive mesopredators, most notably the red fox Vulpes vulpes. The loss of dingoes has been linked to widespread losses of small and medium-sized native mammals, the depletion of plant biomass due to the effects of irrupting herbivore populations and increased predation rates by red foxes. We outline a suite of conceptual models to describe the effects of dingoes on vertebrate populations across different Australian environments. Finally, we discuss key issues that require consideration or warrant research before the ecological effects of dingoes can be incorporated formally into biodiversity conservation programs.

Determining the age of adult wild dogs (Canis lupus dingo, C-l. domesticus and their hybrids). I. Pulp cavity: tooth width ratios

In order to determine the age of adult wild dogs, we compared two methods ( that of Thomson and Rose (TR method) and that of Knowlton and Whittemore (KW method)) of measuring and calculating pulp cavity : tooth width ratios on upper and lower canine teeth from 68 mixed-sex, known-age wild dogs of 9 months to 13 years of age reared at two localities. Although significant relationships ( P = 0.0001) were found between age and pulp cavity ratios by both methods, the TR ratio calculation and measurement showed heteroscedasity in error variance whereas the KW ratios had a more stable error variance and were normally distributed. The KW method also found significant differences between pulp cavity ratios between teeth of the upper and lower jaws ( P < 0.0001) and sex ( P = 0.01) but not geographic origin ( P = 0.1). Regressions and formulae for fitted curves are presented separately for male and female wild dogs. Males show greater variability in pulp cavity decrements with age than do females, suggesting a physiological difference between the sexes. We conclude that the KW method of using pulp cavity as a proportion of tooth width, measured 15 mm from the root tip and averaged over both upper canines, is the more accurate method of estimating the age of adult wild dogs.

Wild dogma: An examination of recent "evidence" for dingo regulation of invasive mesopredator release in Australia

There is growing interest in the role that apex predators play in shaping terrestrial ecosystems and maintaining trophic cascades. In line with the mesopredator release hypothesis, Australian dingoes (Canis lupus dingo and hybrids) are assumed by many to regulate the abundance of invasive mesopredators, such as red foxes Vulpes vulpes and feral cats Felis catus, thereby providing indirect benefits to various threatened vertebrates. Several recent papers have claimed to provide evidence for the biodiversity benefits of dingoes in this way. Nevertheless, in this paper we highlight several critical weaknesses in the methodological approaches used in many of these reports, including lack of consideration for seasonal and habitat differences in activity, the complication of simple track-based indices by incorporating difficult-to-meet assumptions, and a reduction in sensitivity for assessing populations by using binary measures rather than potentially continuous measures. Of the 20 studies reviewed, 15 of them (75%) contained serious methodological flaws, which may partly explain the inconclusive nature of the literature nvestigating interactions between invasive Australian predators. We therefore assert that most of the “growing body of evidence” for mesopredator release is merely an inconclusive growing body of literature only. We encourage those interested in studying the ecological roles of dingoes relative to invasive mesopredators and native prey species to account for the factors we identify, and caution the value of studies that have not done so.

Human-directed gazing behaviour in puppies and adult dogs, Canis lupus familiaris

Recent evidence indicates that dogs' sociocognitive abilities and behaviour in a test situation are shaped by both genetic factors and life experiences. We used the 'unsolvable task' paradigm to investigate the effect of breed and age/experience on the use of human-directed gazing behaviour. Following a genetic classification based on recent genome analyses, dogs were allocated to three breed groups, namely Primitive, Hunting/Herding and Molossoid. Furthermore, we tested dogs at 2 months, 4.5. months and as adults. The test consisted of three solvable trials in which dogs could obtain food by manipulating a plastic container followed by an unsolvable trial in which obtaining the food became impossible. The dogs' behaviour towards the apparatus and the people present was analysed. At 2 months no breed group differences emerged and although human-directed gazing behaviour was observed in approximately half of the pups, it occurred for brief periods, suggesting that the aptitude to use human-directed gazing as a request for obtaining help probably develops at a later date when dogs have had more experience with human communication. Breed group differences, however, did emerge strongly in adult dogs and, although less pronounced, also in 4.5-month-old subjects, with dogs in the Hunting/Herding group showing significantly more human-directed gazing behaviour than dogs in the other two breed groups. These results suggest that, although the domestication process may have shaped the dog's human-directed communicative abilities, the later selection for specific types of work might also have had a significant impact on their emergence. © 2011 The Association for the Study of Animal Behaviour.

Avaliação de Índices de Função Sistólica do Ventrículo Esquerdo em Canis lupus familiaris por Técnica de Ecocardiografia Doppler

A função cardíaca é fortemente condicionada pela mioarquitectura do coração, pelo que o estudo da relação morfologia-função ventricular nos mamíferos é de grande importância no diagnóstico e tratamento de patologias cardíacas. O cálculo dos volumes cardíacos durante todo o ciclo cardíaco tem uma importância fundamental para o estudo da função ventricular e para a definição dos padrões hemodinâmicos. Foi objectivo deste trabalho, o estudo de índices de função sistólica ventricular esquerda, em 25 cães (Cannis lupus familiaris), através da utilização de diferentes técnicas ecocardiográficas, como o Modo M, ecocardiografia bidimensional, Doppler tecidular e a ecocardiografia de contraste. Foi utilizado contraste ultrasonográfico, para melhorar a definição do endocárdio e possibilitar maior rigor no cálculo dos volumes ventriculares, e na avaliação da função ventricular sisto-diastólica global e regional. Os resultados apresentados foram sujeitos a tratamento estatístico com software Analyze-it. O Doppler tecidular mostrou ser um método robusto para avaliar a função sistólica. A ecocardiografia de contraste permitiu não só obter uma melhor definição endocárdica, como obter valores de fracção de ejecção com diferença estatisticamente significativa. Como os três métodos utilizados avaliam diferentes aspectos da função sistólica, função ventricular radial, circunferencial e longitudinal, não podem ser comparados directamente entre si.

Resolving the value of the dingo in ecological restoration

There is global interest in restoring populations of apex predators, both to conserve them and to harness their ecological services. In Australia, reintroduction of dingoes (Canis dingo) has been proposed to help restore degraded rangelands. This proposal is based on theories and the results of studies suggesting that dingoes can suppress populations of prey (especially medium- and large-sized herbivores) and invasive predators such as red foxes (Vulpes vulpes) and feral cats (Felis catus) that prey on threatened native species. However, the idea of dingo reintroduction has met opposition, especially from scientists who query the dingo's positive effects for some species or in some environments. Here, we ask 'what is a feasible experimental design for assessing the role of dingoes in ecological restoration?' We outline and propose a dingo reintroduction experiment-one that draws upon the existing dingo-proof fence-and identify an area suitable for this (Sturt National Park, western New South Wales). Although challenging, this initiative would test whether dingoes can help restore Australia's rangeland biodiversity, and potentially provide proof-of-concept for apex predator reintroductions globally.

Testes cognitivos para avaliação de memória e aprendizado em cães (Canis lupus familiaris)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Clinical feasibility of cognitive testing in dogs (Canis lupus familiaris)

Several cognitive tests have been developed to evaluate specific aspects of human and animal learning and memory. These tests have been used for early detection of cognitive deficits and to monitor the treatment of dogs with cognitive impairment. Thus, this article evaluated the feasibility of cognitive tests for use in canine neurology clinical routines and the suitability of the different tests to accomplish this aim. Fifteen healthy adult dogs were used for the cognitive tests of reward approach learning, object approach learning, object discrimination learning, reversal learning, delayed non-matched to position, and delayed non-matched to sample to assess different aspects of memory. No difference was observed between tests of delayed non-matched to position (3.13 +/- 2.23 days) and delayed non-matched to sample (3.20 +/- 2.40 days) (P = 0.944). However, dogs had greater difficulty in reversal learning (8.47 +/- 2.61 days) than in object discrimination learning (4.60 +/- 1.64 days) (P <= 0.001). Based on the tests performed, the delayed non-matched to position test may be performed in clinical routine if the owner and the veterinarian have time available, because this test is sensitive to evaluate dogs with cognitive impairments, but requires approximately 10 days of training. Thus, elderly dogs are excellent experimental models to study pathological aging based on their similarities with some human brain diseases, such as Alzheimer disease. (C) 2014 Elsevier Inc. All rights reserved.

Infection in domestic dogs (Canis lupus familiaris, Linnaeus, 1758) from Guaratuba, Parana, Brazil by circulating microfilariae of Acanthocheilonema reconditum (Grassi, 1889)

The epidemiologic frameworks of zoonosis periodically change in some of its aspects, involving the emergence or reemergence of men and animals' worsening of health. In this scenario, in which rapid changes can happen, the analysis of the prevalence of diseases, as the filariasis diagnosed in dogs from the coastline of Parana, has significant relevance. This study has been carried out with 422 dogs and aimed to determine the prevalence of circulating microfilariae of Acanthocheilonema reconditum, both in animals accommodated at the municipal kennels, as those that live in the district COHAPAR II, both places located in the metropolitan area of the city of Guaratuba-Parana, through two blood tests: evaluation of fresh blood, by the technique of the 'thick drop' and method of Knott modified by Newton and Wright. Thirty of the evaluated animals (7.10%), twenty two males and eight females, showed the presence of microfilariae of A. reconditum as result.

Respuesta conductual de Canis lupus familiaris a diferentes movimientos gestuales realizados por el ser humano.

Se analiza el comportamiento del perro (Canis lupus familiaris) en función de una serie de movimientos gestuales realizados por humanos (dueño, persona conocida y desconocido). Se observó que el patrón de comportamiento viene determinado por la persona que realiza los gestos. La respuesta de comportamiento se asocia al reconocimiento, o no, de una estructura jerárquica interespecífica, donde el dueño del animal ocupa el mayor rango. Ante personas extrañas el perro no reconoce dicha jerarquización, cambiando claramente su respuesta ante los mismos movimientos gestuales. / The behavior of the dog (Canis lupus familiaris) depending on different universal gestural movements made by different humans individuals was studied (dog owner, person known by the dog and person unknown by the dog). It was observed that the decisive factor is the individual who performs the gestures. The behavioral response is associated with the recognition or not of an interspecific hierarchical structure, and the owner of the animal occupies the highest rank. With strangers the dog does not recognize this hierarchy, changing their response to the same gestural movements.