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Peake, T. M., Terry, A. M. R., McGregor, P. K., & Dabelsteen, T. (2002). Do great tits assess rivals by combining direct experience with information gathered by eavesdropping? Proc Biol Sci, 269(1503), 1925–1929.
Abstract: Animals frequently use signals that travel further than the spacing between individuals. For every intended recipient of a given signal there are likely to be many other individuals that receive information. Eavesdropping on signalling interactions between other individuals provides a relatively cost-free method of assessing future opponents or mates. Male great tits (Parus major) extract relative information from such interactions between individuals unknown to them. Here, we show that male great tits can take information gathering a stage further and obtain more information about a previously unencountered intruder, by the hitherto unknown capability of combining information gathered by eavesdropping with that derived from their own direct interaction with an individual. Prior experience with an intruder (A) was achieved by subjecting a focal male to different levels of intrusion simulated using interactive playback. This intruder (A) then took part in a simulated interaction with an unknown male (B) outside the territorial boundary of the focal males. In response to subsequent intrusion by the second male (B), focal males showed low song output in response to males that had lost to a male that the subject was able to beat. Males of known high quality, or those about which information was ambiguous, elicited a high level of song output by focal males. We discuss the implications of this finding for the evolution of communication and social behaviour.
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Marinier, S. L., Alexander, A. J., & Waring, G. H. (1988). Flehmen behaviour in the domestic horse: Discrimination of conspecific odours. Appl. Anim. Behav. Sci., 19(3-4), 227–237.
Abstract: American Saddlebred horses were used to test the responses of domestic horses to the odours of conspecifics. In all cases the odours were tested in the absence of the donor animal. Thus the test animal's behavioural responses were concentrated on the olfactory stimuli, and possible interference from donor behaviour was eliminated. Stallions were significantly more responsive than mares and geldings. This was shown in both flehmen and sniffing behaviour to urine/vaginal secretions and in sniffing behaviour to faecal samples. Only stallions were used for subsequent tests. Stallions showed no significant differences in response to the odour of urine/vaginal secretions of an oestrus mare from that when she was not in season. Parameters used for analysis of data were frequency, latency and duration of flehmen as well as duration of responsiveness to samples. In testing for differences in odours between individual mares, two methods were used. The stallions differentiated between samples from individual mares. In some cases this differentiation was exhibited when the stallions were merely presented with the two samples in sequence. In other cases statistically significant differences in response to the odours were shown only by simultaneous presentation of the two samples to the test stallion. Parameters used for data analysis were frequency and duration of flehmen and duration of responsiveness.
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Scheffer, M., & van Nes, E. H. (2006). Self-organized similarity, the evolutionary emergence of groups of similar species. Proc. Natl. Acad. Sci. U.S.A., 103(16), 6230–6235.
Abstract: Ecologists have long been puzzled by the fact that there are so many similar species in nature. Here we show that self-organized clusters of look-a-likes may emerge spontaneously from coevolution of competitors. The explanation is that there are two alternative ways to survive together: being sufficiently different or being sufficiently similar. Using a model based on classical competition theory, we demonstrate a tendency for evolutionary emergence of regularly spaced lumps of similar species along a niche axis. Indeed, such lumpy patterns are commonly observed in size distributions of organisms ranging from algae, zooplankton, and beetles to birds and mammals, and could not be well explained by earlier theory. Our results suggest that these patterns may represent self-constructed niches emerging from competitive interactions. A corollary of our findings is that, whereas in species-poor communities sympatric speciation and invasion of open niches is possible, species-saturated communities may be characterized by convergent evolution and invasion by look-a-likes.
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Mettke-Hofmann, C., & Gwinner, E. (2003). Long-term memory for a life on the move. Proc. Natl. Acad. Sci. U.S.A., 100(10), 5863–5866.
Abstract: Evidence is accumulating that cognitive abilities are shaped by the specific ecological conditions to which animals are exposed. Long-distance migratory birds may provide a striking example of this. Field observations have shown that, at least in some species, a substantial proportion of individuals return to the same breeding, wintering, and stopover sites in successive years. This observation suggests that migrants have evolved special cognitive abilities that enable them to accomplish these feats. Here we show that memory of a particular feeding site persisted for at least 12 months in a long-distance migrant, whereas a closely related nonmigrant could remember such a site for only 2 weeks. Thus, it seems that the migratory lifestyle has influenced the learning and memorizing capacities of migratory birds. These results build a bridge between field observations suggesting special memorization feats of migratory birds and previous neuroanatomical results from the same two species indicating an increase in relative hippocampal size from the first to the second year of life in the migrant but not in the nonmigrant.
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Linklater, W. L., Cameron, E. Z., Stafford, K. J., & Minot, E. O. Estimating Kaimanawa feral horse population size and growth. In SCIENCE & RESEARCH INTERNAL REPORT 185.
Abstract: Animal flight behaviour in response to aircraft could have a profound influence
on the accuracy and precision of aerial estimates of population size but is rarely
investigated. Using independent observers on the ground and in the air we
recorded the presence and behaviour of 17 groups, including 136 individually
marked horses, during a helicopter count in New Zealand’s Kaimanawa
Mountains. We also compared the helicopter count with ground-based
estimates using mark-resight and line-transect methods in areas ranging from
20.5 to 176 km2. Helicopter counts were from 16% smaller to 54% larger than
ground-based estimates. The helicopter induced a flight response in all horse
groups monitored. During flight, horse groups traveled from 0.1 up to 2.75 km
before leaving the ground observer’s view and temporarily changed in size and
composition. A tenth of the horses were not counted and a quarter counted
twice. A further 23 (17%) may have been counted twice but only two of the
three observers’ records concurred. Thus, the helicopter count over-estimated
the marked sub-population by at least 15% and possibly by up to 32%. The net
over-estimate of the marked sub-population corresponded to the 17% and 13%
difference between helicopter counts and ground-based estimates in the central
study area and for the largest area sampled, respectively. Feral horse flight
behaviour should be considered when designing methods for population
monitoring using aircraft. We identify the characteristics of the helicopter
count that motivated horse flight behaviour. We compared our own recent
estimate of population growth from measures of fecundity and mortality (λ =
1.096 with an earlier-published one (λ = 1.182, where r = 0.167) that had been
derived by interpolating between the available history of single counts. Our
model of population growth, standardised aerial counts, and historical estimates
of annual reproduction suggest that the historical sequence of counts since
1979 probably over-estimated growth because count techniques improved and
greater effort was expended in successive counts. We used line-transect, markresight
and dung density sampling methods for population monitoring and
discuss their advantages and limitations over helicopter counts.
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Seaman, S. C., Davidson, H. P. B., & Waran, N. K. (2002). How reliable is temperament assessment in the domestic horse (Equus caballus)? Appl. Anim. Behav. Sci., 78(2-4), 175–191.
Abstract: Differences in behavioural characteristics between individuals of the same species are often described as being due to the temperament of the individuals. These differences can have enormous implications for welfare with some individuals apparently being able to adapt to environmental challenge more easily than others. Such differences have resulted in animals often being described as either `active' copers, which try to escape from or remove an aversive stimulus, or `passive' copers, which show no outward signs of a situation being aversive, thus, appearing to be unaffected. Tests previously developed to assess the temperament of animals have been criticised for several reasons. Behaviour is often recorded and categorised using methods that are not objective and tests are generally carried out once with no consideration of whether or not behavioural responses are consistent over time. This study takes these factors into account. The behaviour of 33 horses was recorded in three types of test--an arena test, response to a person and response to an object. In order to test whether or not responses were consistent over time, the tests were repeated three times with an average of 9 days between trials. Test results were validated using responses from questionnaires completed by the farm team leader. The data were analysed using an initial principal component analysis (PCA) and factor analysis. The horses were found to behave consistently over the three trials in their responses in the arena test. The responses to the person test and the object test were similar to each other; however, these responses were not consistent over trials. The behaviour in the arena test was unable to be used to make a prediction of behaviour in the person and object tests and vice versa. The responses shown by the horses did not enable them to be categorised as either active or passive copers. Behavioural responses in the tests were not predictive of the response to a startle test (water spray), nor could they be used to predict status or response to being reintroduced to the group after testing. There was no relationship between the responses in the tests and the ratings given by the farm team leader. It was concluded that horses vary widely in their responses to artificial behavioural tests, with only the responses to an open-field arena test being consistent over time, and therefore, the only type of test which can indicate some core factor of temperament.
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Murphy, J., Sutherland, A., & Arkins, S. (2005). Idiosyncratic motor laterality in the horse. Appl. Anim. Behav. Sci., 91(3-4), 297–310.
Abstract: Idiosyncratic motor behaviour was investigated during four experimental procedures in 40 horses (males = 20, females = 20) to establish if horses revealed evidence of significant right or left laterality. The experimental procedures included (1) detection of the preferred foreleg to initiate movement (walk or trot), (2) obstacle avoidance within a passageway (right or left), (3) obstacle avoidance when ridden and (4) idiosyncratic motor bias when rolling. The influence of the horses' sex on both the direction and the degree of the laterality was explored within and between experimental procedures. The findings showed that the direction, but not the degree of idiosyncratic motor preference in the horses was strongly sex-related. Male horses exhibited significantly more (t = 3.74, d.f. = 79, P < 0.001) left lateralised responses and female horses exhibited significantly more (t = -6.35, d.f. = 79, P < 0.01) right lateralised responses. There was also significant positive correlation (P < 0.05) between four of six possible inter-experimental relationships. The results suggest two discrete trends of laterality associated with the sex of the horse. The primary cause of idiosyncratic motor laterality may be genetically predetermined, influenced by environmental factors or a combination of these two and the current findings may support the development of sex-specific training schedules for the horse. Further, work in this area might assist in defining the mechanisms of brain hemisphere lateralisation and allocation of cognitive function in the horse.
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Nathan J. Emery. (2005). The Evolution of Social Cognition. In The Cognitive Neuroscience of Social BehaviourGarten. Psychology Press.
Abstract: Although this bookis focusedon the cognitive neuroscience ofhuman social behaviour, an
understandingofsocial cognition in non-human animals is critical for unravellingthe neural basis of
social cognition in humans as well as the selective pressures that have shapedthe evolution ofcomplex
social cognition. Thanks to methodological limitations, we know little about the relationships between
certain biochemical andelectrophysiological properties ofthe human brain andhow theycompute the
behaviour andmental states ofother individuals. Traditional techniques for examiningneural function
in humans, such as event-relatedpotentials (ERP),positron emission tomography(PET),and
functional magnetic resonance imaging(fMRI),are constrainedbythe fact that subjects are placed
either into an immoveable scanner with a lot ofbackgroundnoise or wiredup with dozens of
electrodes that are sensitive to slight movements. The possibilityofscanningor recordingbrain waves
from two individuals that are physicallyinteractingsociallyis technicallyimpossible at present
(however, see Montague et al, 2002 for a new methodfor simultaneouslyscanningtwo individuals
interactingvia a computer).
The onlywayto understandthe neurocognitive architecture ofhuman social behaviour is to examine
similar social processes in both human andnon-human animal minds andmake comparisons at the
species level. An additional argument is that traditional human socio-cognitive tasks are dependent on
the use ofstories, cartoons andverbal cues andinstructions (Heberlein & Adolphs, this volume)which
themselves will elicit specific neural responses that have to be eliminatedfrom neural responses
specificallyrelatedto mindreading. Therefore, the development ofnon-verbal tasks wouldprovide a
breakthrough for studies in non-linguistic animals, pre-verbal human infants andhuman cognitive
neuroimaging.
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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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Dunbar, R. (2003). Evolution of the social brain. Science, 302(5648), 1160–1161.
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