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Kruger, K., Gaillard, C., Stranzinger, G., & Rieder, S. (2005). Phylogenetic analysis and species allocation of individual equids using microsatellite data. Journal of Animal Breeding and Genetics, 122(s1), 78–86.
Abstract: Summary The taxonomic status of all equid species is not completely unravelled. This is of practical relevance for conservation initiatives of endangered, fragmented equid populations, such as the Asiatic wild asses (in particular Equus hemionus onager and E. hemionus kulan). In this study, a marker panel consisting of 31 microsatellite loci was used to assess species demarcation and phylogeny, as well as allocation of individuals (n = 120) to specific populations of origin (n = 11). Phylogenetic analysis revealed coalescence times comparable with those previously published from fossil records and mtDNA data. Using Bayesian approaches, it was possible to distinguish between the studied equids, although individual assignment levels varied. The observed results support the maintenance of separate captive conservation herds for E. hemionus onager and E. hemionus kulan. The first molecular genetic results for E. hemionus luteus remained contradictory, as they unexpectedly indicated a closer genetic relationship between E. hemionus luteus and E. kiang holderi compared with the other hemiones.
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Papakostas, Y. G., Daras, M. D., Liappas, I. A., & Markianos, M. (2005). Horse madness (hippomania) and hippophobia. Hist Psychiatry, 16(Pt 4 (no 64)), 467–471.
Abstract: Anthropophagic horses have been described in classical mythology. From a current perspective, two such instances are worth mentioning and describing: Glaucus of Potniae, King of Efyra, and Diomedes, King of Thrace, who were both devoured by their horses. In both cases, the horses' extreme aggression and their subsequent anthropophagic behaviour were attributed to their madness (hippomania) induced by the custom of feeding them with flesh. The current problem of 'mad cow' disease (bovine spongiform encephalopathy) is apparently related to a similar feed pattern. Aggressive behaviour in horses can be triggered by both biological and psychological factors. In the cases cited here, it is rather unlikely that the former were the cause. On the other hand, the multiple abuses imposed on the horses, coupled with people's fantasies and largely unconscious fears (hippophobia), may possibly explain these mythological descriptions of 'horse-monsters'.
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Hare, B., & Tomasello, M. (2005). Human-like social skills in dogs? Trends. Cognit. Sci., 9(9), 439–444.
Abstract: Domestic dogs are unusually skilled at reading human social and communicative behavior--even more so than our nearest primate relatives. For example, they use human social and communicative behavior (e.g. a pointing gesture) to find hidden food, and they know what the human can and cannot see in various situations. Recent comparisons between canid species suggest that these unusual social skills have a heritable component and initially evolved during domestication as a result of selection on systems mediating fear and aggression towards humans. Differences in chimpanzee and human temperament suggest that a similar process may have been an important catalyst leading to the evolution of unusual social skills in our own species. The study of convergent evolution provides an exciting opportunity to gain further insights into the evolutionary processes leading to human-like forms of cooperation and communication.
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Hemelrijk, C. K., Wantia, J., & Gygax, L. (2005). The construction of dominance order: comparing performance of five methods using an individual-based model. Behaviour, 142(8), 1043–1064.
Abstract: In studies of animal behaviour investigators correlate dominance with all kinds of behavioural
variables, such as reproductive success and foraging success. Many methods are used to
produce a dominance hierarchy from a matrix reflecting the frequency of winning dominance
interactions. These different methods produce different hierarchies. However, it is difficult to
decide which ranking method is best. In this paper, we offer a new procedure for this decision:
we use an individual-based model, called DomWorld, as a test-environment. We choose this
model, because it provides access to both the internal dominance values of artificial agents
(which reflects their fighting power) and the matrix of winning and losing among them and,
in addition, because its behavioural rules are biologically inspired and its group-level patterns
resemble those of real primates. We compare statistically the dominance hierarchy based on
the internal dominance values of the artificial agents with the dominance hierarchy produced
by ranking individuals by (a) their total frequency of winning, (b) their average dominance
index, (c) a refined dominance index, the David`s score, (d) the number of subordinates each
individual has and (e) a ranking method based on maximizing the linear order of the hierarchy.
Because dominance hierarchies may differ depending on group size, type of society, and the
interval of study, we compare these ranking methods for these conditions.We study complete
samples as well as samples randomly chosen to resemble the limitations of observing real
animals. It appears that two methods of medium complexity (the average dominance index
and David`s score) lead to hierarchical orders that come closest to the hierarchy based on
internal dominance values of the agents. We advocate usage of the average dominance index,
because of its computational simplicity.
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Digweed, S. M., Fedigan, L. M., & Rendall, D. (2005). Variable specificity in the anti-predator vocalizations and behaviour of the white-faced capuchin, Cebus capucinus. Behaviour, 142(8). Retrieved June 15, 2024, from http://dx.doi.org/10.1163/156853905774405344
Abstract: (Accepted: 23 June 2005)
Summary
Much research in animal communication is aimed at understanding the functional design
features of animal vocal signals. Our detailed analyses of the vocalizations and behavioural
responses elicited in white-faced capuchins by predators and other disturbances point to two
call variants that differ modestly in their acoustic structure and that are accompanied by
functionally distinct behavioural responses. The first variant is given exclusively to avian
predators and is almost invariably accompanied by the monkeys immediate descent from
the treetops where it is most vulnerable; therefore, we label this call variant the aerial
predator alarm?. The second variant, that differs only slightly but noticeably from the first,
is given to a wide range of snakes and mammals, including a range of species that represent
no predatory threat to the monkeys. This second call is also associated with more variable
responses from calling monkeys, from delayed retreat from the source of disturbance, to
active approach, inspection, and sometimes mobbing of the animal involved. We therefore
label this variant more generally as an “alerting call”. Although some other primate species
show a more diverse system of anti-predator calls, and the capuchins themselves may yet
be found to produce a greater variety of calls, a system of two call variants with varying
degrees of predator specificity and behavioural response is not uncommon among primates
and appears functionally appropriate for capuchins. The basic structure of the alerting call
allows conspecific listeners to localize the caller and the source of disturbance readily, thereby
allowing listeners to approach and assist in mobbing in cases where the disturbance warrants
it, or to avoid the area in cases where the disturbance is identified as a predatory threat.
Conversely, the aerial predator alarm is inherently less localizable and therefore conveys the
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Stock, K. F., & Distl, O. (2005). Evaluation of expected response to selection for orthopedic health and performance traits in Hanoverian Warmblood horses. Am J Vet Res, 66(8), 1371–1379.
Abstract: OBJECTIVE: To determine whether selection schemes accounting for orthopedic health traits were compatible with breeding progress in performance parameters in Hanoverian Warmblood horses. ANIMALS: 5,928 horses. PROCEDURE: Relative breeding values (RBVs) were predicted for osseous fragments in fetlock (metacarpo- and metatarsophalangeal) and tarsal joints, deforming arthropathy in tarsal joints, and pathologic changes in distal sesamoid bones. Selection schemes were developed on the basis of total indices for radiographic findings (TIR), dressage (TID), and jumping (TIJ). Response to selection was traced over 2 generations of horses for dressage and jumping ability and all-purpose breeding. Development of mean RBVs and mean total indices in sires and prevalences of orthopedic health traits in their offspring were used to assess response to selection. RESULTS: Giving equal weight toTIR andTID, TIJ, or a combined index of 60% TID and 40% TIJ, 43% to 53% of paternal grandsires and 70% to 82% of descending sires passed selection. In each case, RBVs and total indices increased by as much as 9% in selected sires, when compared with all sires, and prevalences of orthopedic health traits in offspring of selected sires decreased relatively by as much as 16%. When selection was exclusively based on TID, TIJ, or TID and TIJ, percentages of selected sires were 44% to 66% in the first and 73% to 84% in the second generation and TID and TIJ increased by 9% to 10% and 19% to 23%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Compared with exclusively performance-based selection, percentages of selected sires changed slightly and breeding progress in TID, TIJ, or TID and TIJ was only slightly decreased; however, prevalences of orthopedic health traits decreased in offspring of TIR-selected sires.
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Apfelbach, R., Blanchard, C. D., Blanchard, R. J., Hayes, R. A., & McGregor, I. S. (2005). The effects of predator odors in mammalian prey species: A review of field and laboratory studies. Neuroscience and Biobehavioral Reviews, 29(8), 1123–1144.
Abstract: Prey species show specific adaptations that allow recognition, avoidance and defense against predators. For many mammalian species this includes sensitivity towards predator-derived odors. The typical sources of such odors include predator skin and fur, urine, feces and anal gland secretions. Avoidance of predator odors has been observed in many mammalian prey species including rats, mice, voles, deer, rabbits, gophers, hedgehogs, possums and sheep. Field and laboratory studies show that predator odors have distinctive behavioral effects which include (1) inhibition of activity, (2) suppression of non-defensive behaviors such as foraging, feeding and grooming, and (3) shifts to habitats or secure locations where such odors are not present. The repellent effect of predator odors in the field may sometimes be of practical use in the protection of crops and natural resources, although not all attempts at this have been successful. The failure of some studies to obtain repellent effects with predator odors may relate to (1) mismatches between the predator odors and prey species employed, (2) strain and individual differences in sensitivity to predator odors, and (3) the use of predator odors that have low efficacy. In this regard, a small number of recent studies have suggested that skin and fur-derived predator odors may have a more profound lasting effect on prey species than those derived from urine or feces. Predator odors can have powerful effects on the endocrine system including a suppression of testosterone and increased levels of stress hormones such as corticosterone and ACTH. Inhibitory effects of predator odors on reproductive behavior have been demonstrated, and these are particularly prevalent in female rodent species. Pregnant female rodents exposed to predator odors may give birth to smaller litters while exposure to predator odors during early life can hinder normal development. Recent research is starting to uncover the neural circuitry activated by predator odors, leading to hypotheses about how such activation leads to observable effects on reproduction, foraging and feeding. © 2005 Elsevier Ltd. All rights reserved.
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Conradt, L., & Roper, T. J. (2005). Consensus decision making in animals. Trends Ecol Evol, 20(8), 449–456.
Abstract: Individual animals routinely face decisions that are crucial to their fitness. In social species, however, many of these decisions need to be made jointly with other group members because the group will split apart unless a consensus is reached. Here, we review empirical and theoretical studies of consensus decision making, and place them in a coherent framework. In particular, we classify consensus decisions according to the degree to which they involve conflict of interest between group members, and whether they involve either local or global communication; we ask, for different categories of consensus decision, who makes the decision, what are the underlying mechanisms, and what are the functional consequences. We conclude that consensus decision making is common in non-human animals, and that cooperation between group members in the decision-making process is likely to be the norm, even when the decision involves significant conflict of interest.
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Whiten, A., Horner, V., & de Waal, F. B. M. (2005). Conformity to cultural norms of tool use in chimpanzees. Nature, 437(7059), 737–740.
Abstract: Rich circumstantial evidence suggests that the extensive behavioural diversity recorded in wild great apes reflects a complexity of cultural variation unmatched by species other than our own. However, the capacity for cultural transmission assumed by this interpretation has remained difficult to test rigorously in the field, where the scope for controlled experimentation is limited. Here we show that experimentally introduced technologies will spread within different ape communities. Unobserved by group mates, we first trained a high-ranking female from each of two groups of captive chimpanzees to adopt one of two different tool-use techniques for obtaining food from the same 'Pan-pipe' apparatus, then re-introduced each female to her respective group. All but two of 32 chimpanzees mastered the new technique under the influence of their local expert, whereas none did so in a third population lacking an expert. Most chimpanzees adopted the method seeded in their group, and these traditions continued to diverge over time. A subset of chimpanzees that discovered the alternative method nevertheless went on to match the predominant approach of their companions, showing a conformity bias that is regarded as a hallmark of human culture.
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de Waal, F. B. M. (2005). A century of getting to know the chimpanzee. Nature, 437(7055), 56–59.
Abstract: A century of research on chimpanzees, both in their natural habitat and in captivity, has brought these apes socially, emotionally and mentally much closer to us. Parallels and homologues between chimpanzee and human behaviour range from tool-technology and cultural learning to power politics and intercommunity warfare. Few behavioural domains have remained untouched by this increased knowledge, which has dramatically challenged the way we view ourselves. The sequencing of the chimpanzee genome will no doubt bring more surprises and insights. Humans do occupy a special place among the primates, but this place increasingly has to be defined against a backdrop of substantial similarity.
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