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McPhee, M. E., Segal, A., & Johnston, R. E. (2010). Hamsters Use Predator Odors as Indirect Cues of Predation Risk. Ethology, 116(6), 517–523.
Abstract: Abstract Golden hamsters (Mesocricetus auratus) use olfactory cues to assess traits of conspecifics such as kinship, individual identity, and reproductive status. The environment, however, is full of a wide variety of other olfactory information such as signals emitted by some of the hamster’s primary predators. Given this, we hypothesized that hamsters use odors from predators as an indirect sign of increased predation risk in the environment. In addition, based on data that show that wild hamsters are diurnal while laboratory hamsters are nocturnal, we hypothesized that if golden hamsters did respond to the predator odors, perceived predator risk might influence daily activity patterns in hamsters. We tested male and female hamsters over 5 d with scent gland secretion from domestic ferrets (Mustela putorius furo) and compared their behavior to that observed when they were exposed to a clean arena. In response to the predator odor, subjects significantly decreased the amount of time active outside of their burrow, returned to their burrow more quickly, and spent less time near the predator odor than the clean control stimulus. These results strongly support our hypothesis that hamsters, like other species of small mammals, avoid predator odors. The results did not, however, support our second hypothesis that exposure to predator odors during the dark phase of the light cycle would elicit a switch to a more diurnal pattern of activity. More work is needed to understand how environmental cues and internal mechanisms interact to shape activity patterns.
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Llusia, D., Márquez, R., & Beltrán, J. F. (2010). Non-Selective and Time-Dependent Behavioural Responses of Common Toads (Bufo bufo) to Predator Acoustic Cues. Ethology, 116(12), 1146–1154.
Abstract: Abstract Acoustic predator recognition has rarely been studied in anurans, in spite of the fact that hearing is widespread in these animals and that it has been demonstrated to play an important role in both arthropods and other vertebrates. Using field playback experiments, we tested the hypothesis that adult common toads (Bufo bufo) are capable of recognizing natural vocalizations of a common predator, the Eurasian otter (Lutra lutra), and show antipredator responses. We found that toads exposed to both natural (two types of otter sounds) and synthetic stimuli [white noise (WN) and otter sound-based amplitude modulated WN] increased time allocated to locomotion and escape behaviour. These responses were correlated with time elapsed from sunset to the onset of testing and were independent from the type of acoustic signal, toad features and other environmental factors monitored. We conclude that B. bufo has not developed a selective recognition of predator vocalizations, suggesting that low-frequency or seismic sounds associated with predator movements may provide anurans with better cues about an approaching risk. We propose that the time-dependent response to acoustic stimuli of common toads represents a case of threat-sensitivity and demonstrates that it can occur even when the response to the threat is not predator specific.
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Biondi, L. M., García, G. O., Bó, M. S., & Vassallo, A. I. (2010). Social Learning in the Caracara Chimango, Milvago chimango (Aves: Falconiformes): an Age Comparison. Ethology, 116(8), 722–735.
Abstract: Abstract Milvago chimango is a gregarious raptor showing great ecological plasticity. Their ability to explore new resources has allowed them to survive in areas with increasing human modification. In this study, we evaluated the social learning ability in wild-caught individuals of M. chimango. In particular, we tested whether an ‘observer’ individual could improve the acquisition of a novel behaviour by watching a ‘demonstrator,’ and we examined the effects of age of both observers and demonstrators on social learning. We measured the ability of 18 observers to open an opaque Plexiglas box containing food, and we compared their performance to that of 10 control birds who did not watch a demonstrator solve the task. Prior to watching a demonstrator, only two of the observers and two of the control birds were able to open the box. After watching a demonstrator, 67% of observers were able to open the box, outperforming control birds in speed and success. Juvenile observers were more successful and faster than adults at contacting and opening the box. The age of the demonstrator did not influence the observers’ likelihood of success. These results showed that M. chimango are able to learn a box-opening task with a hidden food reward by observing the behaviour of a conspecific and that this behaviour persisted over several days. Social learning ability in M. chimango might allow certain behavioural patterns, such as those related to novel resource acquisition in modified environments, to be socially transmitted among individuals in a population.
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Dochtermann, N. A., & Jenkins, S. H. (2011). Multivariate Methods and Small Sample Sizes. Ethology, 117(2), 95–101.
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Black, J. M. (1988). Preflight Signalling in Swans: A Mechanism for Group Cohesion and Flock Formation. Ethology, 79(2), 143–157.
Abstract: Abstract The preflight behaviour of whooper swans Cygnus cygnus and Bewick's swans Cygnus columbianus bewickii was examined to determine the adaptive significance of the ritual. Analysis of the preflight sequence revealed that the rate of signalling became significantly faster as the time of takeoff approached. This provides the first quantitative evidence that a threshold of excitability is responsible for triggering synchronised flight in social units. Two ultimate and two proximate factors that affect this threshold were uncovered. They are: 1) Maintaining proximity to partners—flight was delayed by birds with non-attentive mates and signalling lasted on average four times longer than those whose mates showed more interest. 2) Maintaining flock cohesiveness—birds which performed signals for longer periods while swimming among uninterested birds were successful in attracting followers 61% of the time. 3) The bird's feeding performance related to dominance status—less successful feeders (potentially hungry birds), flew after little time and few signals. 4) The type of feeding opportunity at the eventual destination—birds which flew to provided feeds (nutritious barley) spent less time performing preflight signals than when they flew to forage on grass fields.
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Huang, S. - P., Yang, S. - Y., & Hsu, Y. (2011). Persistence of Winner and Loser Effects Depends on the Behaviour Measured. Ethology, 117(2), 171–180.
Abstract: Abstract Recent contest experience can influence an individual’s behaviour in subsequent contests. When the probability of winning a subsequent contest is used to quantify experience effects, a loser effect usually lasts longer than a winner effect. This conclusion, however, may be caused by this probability understating the persistence of the influence of a winning experience on contest decisions. Using Kryptolebias marmoratus, a mangrove killifish, as the study organism, we investigated whether different conclusions about the relative persistence of winning and losing experiences would be reached when different aspects of contest behaviour (probability of initiating attacks, probability of winning non-escalated and escalated contests, escalation rate and contest duration) were measured. The results indicated that the apparent persistence of the effect of winning or losing experiences varied with the behaviour studied. When the likelihood to initiate attacks was used, no winner effect was detected while the loser effect lasted for <1 d. When escalation rate was used, the winner effect lasted for 2–4 d, while the loser effect lasted for 1–2 d. When the probability of winning non-escalated contests was used, the winner effect was detectable for <1 d, while the loser effect lasted for 2–4 d. And, when contest duration was used, the winner effect was detectable for 2–4 d, but no loser effect was detectable. These results show that (1) the probability of winning a subsequent contest understated the persistence of the influence of a winning experience on the fish’s contest decisions, (2) the measures most effective at detecting winner effects are different from those most effective at detecting loser effects and (3) in K. marmoratus, both effects can be detected 2 d after the completion of experience training but both dissipate in 4 d.
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Mersmann, D., Tomasello, M., Call, J., Kaminski, J., & Taborsky, M. (2011). Simple Mechanisms Can Explain Social Learning in Domestic Dogs (Canis familiaris). Ethology, 117(8), 675–690.
Abstract: Abstract Recent studies have suggested that domestic dogs (Canis familiaris) engage in highly complex forms of social learning. Here, we critically assess the potential mechanisms underlying social learning in dogs using two problem-solving tasks. In a classical detour task, the test dogs benefited from observing a demonstrator walking around a fence to obtain a reward. However, even inexperienced dogs did not show a preference for passing the fence at the same end as the demonstrator. Furthermore, dogs did not need to observe a complete demonstration by a human demonstrator to pass the task. Instead, they were just as successful in solving the problem after seeing a partial demonstration by an object passing by at the end of the fence. In contrast to earlier findings, our results suggest that stimulus enhancement (or affordance learning) might be a powerful social learning mechanism used by dogs to solve such detour problems. In the second task, we examined whether naïve dogs copy actions to solve an instrumental problem. After controlling for stimulus enhancement and other forms of social influence (e.g. social facilitation and observational conditioning), we found that dogs’ problem solving was not influenced by witnessing a skilful demonstrator (either an unknown human, a conspecific or the dog’s owner). Together, these results add to evidence suggesting that social learning may often be explained by relatively simple (but powerful) mechanisms.
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Noë, R., van Schaik, C. P., & van Hooff, J. A. R. A. M. (1991). The Market Effect: an Explanation for Pay-off Asymmetries among Collaborating Animals. Ethology, 87(1-2), 97–118.
Abstract: Abstract * 1Animals can derive leverage over others from (a) resource holding power, based for instance on fighting ability or dominance, and (b) the possession of commodities, such as special skills and resources that cannot be taken away by force. * 2We contend that power based on the possession of commodities strongly depends on the level of supply and demand for that commodity, a phenomenon we call the ‘market effect’. * 3Several theoretical and empirical examples are given of social systems in which animals belong to two distinct classes that offer two different kinds of commodities. * 4The relative frequency of occurrence of the two classes is shown to determine the relative power of their members. * 5We consider the theoretical properties of bargaining processes by which relative power is converted into corresponding pay-off distributions. * 6We propose coalition games, a class of games with more than two players and in which bargaining is possible, as suitable paradigms for collaboration among members of social units.
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Hemelrijk, C. K. (2002). Understanding Social Behaviour with the Help of Complexity Science (Invited Article). Ethology, 108(8), 655–671.
Abstract: Abstract In the study of complexity, a new kind of explanation has been developed for social behaviour. It shows how patterns of social behaviour can arise as a side-effect of the interaction of individuals with their social or physical environment (e.g. by self-organization). This development may influence our ideas about the direct causation and evolution of social behaviour. Furthermore, it may influence our theories about the integration of different traits. This new method has been made possible by the increase in computing power. It is now applied in many areas of science, such as physics, chemistry, sociology and economics. However, in zoology and anthropology it is still rare. The major aim of this paper is to make this method more generally accepted among behavioural scientists.
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Baragli, P., Paoletti, E., Vitale, V., & Sighieri, C. (2011). Looking in the correct location for a hidden object: brief note about the memory of donkeys (Equus asinus). Ethology Ecology & Evolution, 23(2), 187–192.
Abstract: In recent years, considerable literature has been published on cognition in horses; however, much less is known about the cognitive abilities of domestic donkey (Equus asinus). This study aimed to expand our knowledge of donkey cognition by assessing their short-term memory capacity. We employed a detour problem combined with the classic delayed-response task, which has been extensively used to compare working memory duration in a variety of different species. A two-point choice apparatus was used to investigate location recall and search behaviour for a food target, after a short delay following its disappearance. Four donkeys completed the task with a 10 sec delay, while four others were tested with a 30 sec delay. Overall, each group performed above chance level on the test, showing that subjects had successfully encoded, maintained, and retrieved the existence and location of the target despite the loss of visual contact.
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