Abstract: The objective of the study was to determine which cross-country obstacles are more difficult for eventing horses. Jumping scores were considered in terms of the horse's reaction to novelty and to the fearfulness of novel objects which are the fences situated in novel terrain. The data concerned 11 classes of One to Four Star level (stars showing the difficulty of the class) held at the Olympic Games and three international Three Day Events. A total of 400 entries, in which 259 horses jumped 372 obstacles were considered. Scores of 11,341 jumps at particular fences were categorized either as faulty jumps or non-faulty jumps. Factors describing the fences versus the jumping scores were studied with least square analysis of variance, with respect to the interaction between the star level and the fence traits. The overall frequency of faults at the cross-country amounted to 4.33 ± 0.57%. Among the effects analyzed, the difficulty of cross-country fences for the horses depends upon whether an obstacle is single or is an element of a combination, whether it is straight or requiring an effort in both height and spread, is broad or narrow, has a solid top or a brush, has an alternative or not and whether it is a water crossing or not. At One Star level, the less experienced horses react differently to certain fence traits compared to horses participating in Three or Four Star levels. It is concluded that the equine visionary system, being less developed towards identification of stationary objects than the human visionary system may be a key towards explaining the horse's behaviour while jumping the obstacle. The height-spread obstacles, those of the narrow front, with the brush and with the alternative seem to involve more faults because of the equine low-acuity vision. The same reason may justify the similar frequency of faults at the single obstacles and the first elements in combinations. Accurate methods of measuring equine vision would complement behavioural tests and should both be introduced into the selection of eventing horses.

Abstract: Experimental analyses of dynamic visual signals have to overcome the technical obstacle of reproducing complex motor patterns such as those found in courtship and threat displays. Video playback offers a potential solution to this problem, but it has recently been criticized because of sensory differences between humans and nonhuman animals, which suggest that video stimuli might be perceived as deficient relative to live conspecifics. Quantitative comparisons are therefore necessary to determine whether video sequences reliably evoke natural responses. Male Jacky dragons, Amphibolurus muricatus, compete for territories using complex displays delivered in a rapid stereotyped sequence. We evaluated video playback as a technique for studying this visual signal. Digital video sequences depicting a life-sized displaying male were indistinguishable from live male conspecifics in the rate and structure of aggressive displays evoked. Other measures of social behaviour suggested that video stimuli were more effective in this context. Lizards produced significantly more appeasement displays and had higher rates of substrate licking and locomotor activity in response to video playback than to confined male opponents, which failed to produce aggressive displays. Lizards tracked temporal changes in the display rate of video stimuli and were also sensitive to individual differences in morphology and behaviour between video exemplars. These results show that video stimuli are appropriate for the experimental analysis of Jacky dragon aggressive displays. We compare the potential shortcomings of video playback with those of other techniques and conclude that no approach offers a panacea, but that several have complementary characteristics. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.

Abstract: We investigated how plains zebras moved across a large natural landscape by analysing the movement paths of nine zebra mares foraging out from spatially confined waterholes during the dry season in the Makgadikgadi Pans National Park, Botswana. Since it was essential to investigate directed movement over a range of spatial scales to determine the correct movement behaviour and strategy, we used Nams's scaling test for oriented movement. Zebras followed directed movement paths in the lower to medium spatial scales (10 m–3.7 km) and above their visual, and possibly olfactory, range. The spatial scale of directed movement suggests that zebras had a well-defined spatial awareness and cognitive ability. Seven zebras used directed movement paths, but the remaining two followed paths not significantly different to a correlated random walk (CRW). At large spatial scales (>3 km) no distinct movement pattern could be identified and paths could not be distinguished from a CRW. Foraging strategy affected the extent of directed movement: zebras with a confined dispersion of grazing patches around the central place directed their movements over a longer distance. Zebras may extend the distance at which they can direct their movement after improving their knowledge of the local environment.

Abstract: This study explored whether or not horses (Equus caballus) could respond to stimuli using a concept based on relative size. In Experiment 1, after learning to respond to the larger of the two stimuli for six sets of two-dimensional (2D) training exemplars, one horse was tested for size transposition that used novel larger and smaller stimuli as well as three-dimensional (3D) objects (5 two-dimensional sets and 5 three-dimensional sets with large, medium, small, and tiny sizes). The horse correctly chose (significantly above chance) the larger of two stimuli regardless of novelty or dimension or combination. In Experiment 2, two additional horses were tested using a subset of the stimuli from Experiment 1. One horse was required to select the larger stimulus--as in Experiment 1--and the other the smaller stimulus. After learning the task, both horses responded correctly to new stimuli and showed size transposition. These results suggest that at least some horses are capable of solving problems based on relative size concepts. Moreover, they are able to generalize across situations that vary from flat, black shapes to objects of different materials and colors including balls, flower pots, and PVC connectors. These findings support earlier research that showed that horses could categorize certain stimuli, and provide new evidence that they are capable of using some form of concept for problem solving. Understanding that horses have more advanced learning abilities than was previously believed should help improve training methods and management.