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Rumiantsev, S. N. (1973). [Biological function of Clostridium tetani toxin (ecological and evolutionary aspects)]. Zh Evol Biokhim Fiziol, 9(5), 474–480.
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Mirzaeva, A. G. (1974). [Age makeup of female Culicoides sinanoensis Tok. in the coniferous-broad-leaved forest zone of the southern Maritime Territory]. Parazitologiia, 8(6), 524–530.
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Kiltie, R. A., Fan, J., & Laine, A. F. (1995). A wavelet-based metric for visual texture discrimination with applications in evolutionary ecology. Math Biosci, 126(1), 21–39.
Abstract: Much work on natural and sexual selection is concerned with the conspicuousness of visual patterns (textures) on animal and plant surfaces. Previous attempts by evolutionary biologists to quantify apparency of such textures have involved subjective estimates of conspicuousness or statistical analyses based on transect samples. We present a method based on wavelet analysis that avoids subjectivity and that uses more of the information in image textures than transects do. Like the human visual system for texture discrimination, and probably like that of other vertebrates, this method is based on localized analysis of orientation and frequency components of the patterns composing visual textures. As examples of the metric's utility, we present analyses of crypsis for tigers, zebras, and peppered moth morphs.
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Shoshani, J., Kupsky, W. J., & Marchant, G. H. (2006). Elephant brain. Part I: gross morphology, functions, comparative anatomy, and evolution. Brain Res Bull, 70(2), 124–157.
Abstract: We report morphological data on brains of four African, Loxodonta africana, and three Asian elephants, Elephas maximus, and compare findings to literature. Brains exhibit a gyral pattern more complex and with more numerous gyri than in primates, humans included, and in carnivores, but less complex than in cetaceans. Cerebral frontal, parietal, temporal, limbic, and insular lobes are well developed, whereas the occipital lobe is relatively small. The insula is not as opercularized as in man. The temporal lobe is disproportionately large and expands laterally. Humans and elephants have three parallel temporal gyri: superior, middle, and inferior. Hippocampal sizes in elephants and humans are comparable, but proportionally smaller in elephant. A possible carotid rete was observed at the base of the brain. Brain size appears to be related to body size, ecology, sociality, and longevity. Elephant adult brain averages 4783 g, the largest among living and extinct terrestrial mammals; elephant neonate brain averages 50% of its adult brain weight (25% in humans). Cerebellar weight averages 18.6% of brain (1.8 times larger than in humans). During evolution, encephalization quotient has increased by 10-fold (0.2 for extinct Moeritherium, approximately 2.0 for extant elephants). We present 20 figures of the elephant brain, 16 of which contain new material. Similarities between human and elephant brains could be due to convergent evolution; both display mosaic characters and are highly derived mammals. Humans and elephants use and make tools and show a range of complex learning skills and behaviors. In elephants, the large amount of cerebral cortex, especially in the temporal lobe, and the well-developed olfactory system, structures associated with complex learning and behavioral functions in humans, may provide the substrate for such complex skills and behavior.
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Vieuille, C., Berger, F., Le Pape, G., & Bellanger, D. (2003). Sow behaviour involved in the crushing of piglets in outdoor farrowing huts--a brief report. Appl. Anim. Behav. Sci., 80(2), 109–115.
Abstract: This study focuses on maternal activities involved in the trapping of piglets by the sow's body in outdoor farrowing systems and examine the mother-piglet context leading either to the death of piglets or to their survival. The behaviour of six Large-WhitexLandrace sows and their litters was continuously video recorded at their first and second parity, during the 40 h following parturition. Crushing mainly occurred at evening and night, during the first 12 h of farrowing and involved changes between lying, sitting and standing positions, as well as between udder and side lying. No piglet died from savaging. Nevertheless, aggressive behaviours of sows were observed, particularly in their first maternal experience. The immediate context of trapping was related to the labour of the sow and to the feeding and resting of piglets. The immediate crushing context was related to active avoidance of restless piglets while lying down, as well as sitting and standing behaviours. These results are discussed in terms of differential reactions of the sow to suckling attempts of piglets.
Keywords: Pig-maternal behaviour; Crushing; Free-ranging; Welfare
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Puppe, B., Langbein, J., Bauer, J., & Hoy, S. (2008). A comparative view on social hierarchy formation at different stages of pig production using sociometric measures. Livestock Science, 113(2-3), 155–162.
Abstract: A standardised and comprehensive approach to describe dominance relationships in gregarious farm animals quantitatively was recently developed, incorporating a combination of appropriate sociometric measures. The present study applied this approach to a comparative analysis of the social hierarchies within 57 groups of domestic pigs at different age/production stages with a total of 496 animals. Unacquainted pigs were grouped to three age categories which correspond to the typical production stages: weaned pigs (PIG28, 12 groups), growing pigs (PIG80, 16 groups), and reproductive sows (SOW, 29 groups). Based on observed agonistic interactions, sociometric values were calculated both at the dyadic and at the group level and may be considered as preliminary reference values for further studies. As indicated by the respective values of the Kendall index (PIG28: 0.66, tested as significant in 69.0% of the observed groups; PIG80: 0.71, 87.5%; SOW: 0.61, 69.0%), and the improved Landau index (PIG28: 0.70, 75.0%; PIG80: 0.72, 93.7%; SOW: 0.71, 72.4%), a social organisation towards a quasi-linear social hierarchy was predominantly developed throughout all age/production categories. However, compared to weaned and growing pigs, sows were characterised by significant differences concerning establishment (fewer agonistic interactions) and kind (more unknown dyads, fewer two-way and significant dyads, higher directional consistency index) of their social hierarchy. It seems that sows have effectively adapted their agonistic behaviour towards pen-mates to regulate social dominance relationships, whereas younger pigs frequently display agonistic interactions also to gain additional experience on social cues (e.g. the fighting ability of an opponent). Hence, it is concluded that the effective experience of socialisation during sensitive periods may increase the social skills of pigs which in turn can improve their welfare and health, e.g. by adjusted aggressive behaviour. The consideration of comparable and standardised sociometric measures in livestock breeding may help to improve husbandry conditions.
Keywords: Pig; Dominance; Sociometric measures; Social hierarchy; Ontogeny
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Langbein, J., & Puppe, B. (2004). Analysing dominance relationships by sociometric methods--a plea for a more standardised and precise approach in farm animals. Appl. Anim. Behav. Sci., 87(3-4), 293–315.
Abstract: Social dominance is a multidimensional phenomenon occurring in all gregarious farm animals and finds its reflection in a dominance hierarchy. Hence, numerous studies have tried to analyse dominance relationships as well as to correlate outcoming results (mostly individual ranks) with other behavioural and/or physiological features of the animals. Although the concept of dominance, once established, has been developed continuously and several sociometric measures were cumulatively introduced, a consistent analysing approach has not been achieved, especially in farm animals. Thus, considerable inconsistencies in the used methodology may impair obtained results and interpretations. The present paper is a plea for a more standardised and complex approach when analysing dominance relationships, not only in farm animals. First, derived from a structural definition of dominance, we suggest in detail the preferably consistent use of appropriate sociometric measures at all social levels of analysis: the dyad as the starting level, the group as the highest level, and the individual as the basic level. Second, we applied this procedures in a case study to analyse social dominance in a group of dwarf goats (n=12) and pigs (n=10), respectively, to comparatively demonstrate benefits and problems of such an approach in two different farm animal species. It is concluded that the use of individual ranks is actually only reasonable when fundamental sociometric measures both at the dyadic level (e.g. percentage of dyads which have a significant asymmetric outcome) and at the group level (e.g. the strength of hierarchy) are successfully tested by statistical methods as also presented in this paper. The calculated sociometric measures deliver not only a more comprehensive “picture” of the social relationships within a group as simple ranks do, but also indicate possible reasons of differences in the behavioural development. For instance, whereas the dwarf goats maintained a quasi-linear dominance hierarchy over time with a high rate of overt agonistic behaviour, pigs after the establishment of their hierarchy showed a reduced agonistic behaviour which makes it questionable to calculate reliable sociometric measures. These species-dependent variations may be primarily caused by different kinds of the fighting behaviour in goats (i.e. ritualised, low costs) and pigs (i.e. more seriously, high costs). Overall, a more consistent and standardised approach of analysing social dominance in (farm) animals may improve the scientific value of single studies and makes it easier to compare various studies within a species and between species.
Keywords: Dominance; Dyads; Social hierarchy; Sociometric measures; Pig; Dwarf goat
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Koba, Y., & Tanida, H. (1999). How do miniature pigs discriminate between people? The effect of exchanging cues between a non-handler and their familiar handler on discrimination. Appl. Anim. Behav. Sci., 61(3), 239–252.
Abstract: Behavioural tests using operant conditioning were conducted to examine how miniature pigs discriminate between people. During a 3-week handling period, six 8-week-old pigs were touched and fed raisins as a reward whenever they approached their handler. In subsequent training, the handler and a non-handler wearing dark blue and white coveralls, respectively, and wearing different eau de toilette fragrances sat at each end of a Y-maze. Pigs were rewarded with raisins when they chose the handler. Successful discrimination occurred when the pig chose the handler at least 15 times in 20 trials (P<0.05: by χ2 test). When all pigs exhibited successful discrimination under these standard conditions, they were exposed to Experiments 1 through 4. In Experiment 1, (1) handler and non-handler exchanged colours of coveralls; (2) handler and non-handler exchanged eau de toilette; (3) handler and non-handler exchanged both cues. The non-handler was chosen significantly more often following the exchange of coverall colours and the exchange of both coverall colours and eau de toilette. However, the handler was chosen significantly more frequently following exchange of eau de toilette only. In Experiment 2, when both handler and non-handler wore coveralls of the handler's original colour, the pigs had difficulty discriminating between them. In Experiment 3, both handler and non-handler wore coveralls of new colours. The pigs easily chose the handler wearing red or blue vs. white coveralls. In Experiment 4, (1) two novel people wore coveralls of the original colours of handler and non-handler; (2) the test with the original experimenters was conducted under the original conditions but in a novel place. Between novel people, the one wearing the handler's original colour of coveralls was preferentially chosen by the pigs. The pigs had difficulty discriminating the handler from the non-handler in a novel place. Pigs appear to discriminate between a familiar handler and a non-familiar person based primarily on visual cues, prominent of which is colour of clothing.
Keywords: Pigs; Handling; Learning; Human-animal relationships
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Koba, Y., & Tanida, H. (2001). How do miniature pigs discriminate between people?: Discrimination between people wearing coveralls of the same colour. Appl. Anim. Behav. Sci., 73(1), 45–58.
Abstract: Seven experiments were conducted on four miniature pigs to determine: (1) whether the pigs can discriminate between people wearing the same coloured clothing; (2) what cues they rely on if they could discriminate. For 2 weeks before the experiments began, the pigs were conditioned in a Y-maze to receive raisins from the rewarder wearing dark blue coveralls. They were then given the opportunity to choose the rewarder or non-rewarder in these experiments. Each session consisted of 20 trials. Successful discrimination was that the pig chose the rewarder at least 15 times in 20 trials (P<0.05: by χ2-test). In Experiment 1, both rewarder and non-rewarder wore dark blue coveralls. By 20 sessions, all pigs successfully identified the rewarder. In Experiment 2: (1) both wore coveralls of the same new colours or (2) one of them wore coveralls of new colours. They significantly preferred the rewarder even though the rewarder and/or non-rewarder wore coveralls of new colours. In Experiment 3, both wore dark blue coveralls but olfactory cues were obscured and auditory cues were not given. The pigs were able to identify the rewarder successfully irrespective of changing auditory and olfactory cues. In Experiment 4, both wore dark blue coveralls but covered part of their face and body in different ways. The correct response rate decreased when a part of the face and the whole body of the rewarder and non-rewarder were covered. In Experiment 5, both wore dark blue coveralls and changed their apparent body size by shifting sitting position. The correct response rate increased as the difference in body size between the experimenters increased. In Experiment 6, the distance between the experimenters and the pig was increased by 30 cm increments. The correct response rate of each pig decreased as the experimenters receded from the pig, but performance varied among the pigs. In Experiment 7, the light intensity of the experimental room was reduced from 550 to 80 lx and then to 20 lx. The correct response rate of each pig decreased with the reduction in light intensity, but all the pigs discriminated the rewarder from the non-rewarder significantly even at 20 lx. In conclusion, the pigs were able to discriminate between people wearing coveralls of the same colour after sufficient reinforcement. These results indicate that pigs are capable of using visual cues to discriminate between people.
Keywords: Pigs; Learning; Recognition; Human-animal relationships
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Knopff, K., & Pavelka, M. (2006). Feeding Competition and Group Size in Alouatta pigra. Int. J. Primatol., 27(4), 1059–1078.
Abstract: Researchers consider group size in primates to be determined by complex relationships among numerous ecological forces. Antipredator benefits and better resource defense are the primary pressures for large groups. Conversely, intragroup limited food availability, can result in greater intragroup feeding competition and individual energy expenditure in larger groups, creating energetic advantages for individuals in small groups and placing an upper limit group size. However, the extent to which food availability constrains group size remains unclear for many species, including black howlers (Alouatta pigra), which ubiquitously live in small social groups (≤10 individuals). We studied the relationship between group size and 2 key indices of feeding competition-day journey length and activity budgets in 3 groups of wild Alouatta pigra at a hurricane-damaged site in Belize, Central America. We controlled for differences in food availability between home ranges (food tree density) and compared both indicators of feeding competition directly with temporal variation in food availability for each group. Our results show no consistent association between resource availability, group size, and either index of competition, indicating that feeding competition does not limit group size at the site i.e., that larger groups can form without increased costs of feeding competition. The results support the search for other explanations, possibly social ones, for small group size in the primates, and we conclude with suggestions and evidence for such alternative explanations.
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