Abstract: Animals that are familiar with their environment have been reported to have greater survivorship for a number of reasons related to their knowledge of the terrain, which they recall from memory. In an initial experiment rainbowfish significantly improved their escape response towards a novel trawl apparatus over a sequence of five runs. Escape latencies were still low during a subsequent exposure 11 months after the initial exposure. While part of the improvement in escape success was certainly due to learning associated with the location of the escape route, it is likely that this was aided by habituation to the tank environment and the experimental protocol. In a follow-up experiment, fish that had been kept in the experimental tank for 3 weeks prior to testing, and had become familiar with the test tank, showed significantly lower escape latencies and escaped more often than fish that were not familiar with the test environment. It is suspected that familiarity with the testing arena decreased stress and enabled individuals to detect novel stimuli and devote more attention to them. These findings have significant implications for experimenters studying aspects of animal cognition, such as learning and memory, in laboratory situations.

Abstract: Two experiments assessed the ability of four adult female chimpanzees to categorize natural objects. Chimpanzees were initially trained to match different color photographs of familiar objects from four possible categories. In training, all the comparison stimuli were from the same category in one condition, and from different categories in another condition. For all subjects, training performance was consistently better for the “different category” than for the “same category” trials. Probe trials were shown after training. In probe trials, the sample and positive comparison stimuli were different items from the same category, and the foils were selected from among the three other test categories. Individual performance was above chance in probe trials, suggesting that categorization by chimpanzees may transcend perceptual resemblance. These results were later replicated with novel stimulus items from the same four categories (experiment 2). Altogether, this research demonstrates that chimpanzees grouped perceptually different exemplars within the same category, and further suggests that these animals formed conceptual representations of the categories.

Abstract: Turtles (Pseudemys scripta) were trained in place, cue and control open-field procedures. The turtles trained in both the place and the cue procedures were able to learn their respective tasks with accuracy. Subsequent probe tests revealed that the turtles trained in the place task relied on the information provided by the extramaze cues to locate the goal. However, for these animals, no single cue was essential for performance, as accurate navigation to the goal was still possible when subsets of extramaze cues were eliminated. Furthermore, the turtles trained in the place task were able to navigate accurately to the goal place from new start locations. These results suggest that the turtles trained in the place task used map-like, relational strategies, by encoding the simultaneous spatial relationships between the goal and the extramaze cues in an allocentric frame of reference. In contrast, the turtles trained in the cue procedure used guidance strategies, i.e. approaching the individual intramaze cue associated to the goal as it were a beacon and largely ignoring the extramaze cues. Thus, the results of this experiment suggest that turtles are able to employ spatial strategies that closely parallel those described in mammals and birds.

Abstract: 'Mindreading' or theory of mind (ToM) refers to the capacity to attribute mental states to others. This ability is regarded as a critical component of what has, to date, exclusively characterized the advanced social cognition displayed by humans. The false belief task is a key test for ToM in different animal species. On a standard non-verbal false belief task, humans pass from age 4, whereas non-human primates consistently fail. Neuroanatomical and behavioural evidence for dolphins, however, indicates that they are capable of passing ToM tasks. The current paper represents a synthesis of the relevant dolphin research on neocortical evolution and non-invasive behavioural tests of precursors for ToM and the attribution of beliefs. The success of dolphins on attribution of belief tasks, in the absence of learning or cueing, indicates that they are capable of 'mindreading'. What are the implications of animal 'mindreading'? ToM tasks probe for reflexive consciousness and, by this criterion, dolphins may display reflexive consciousness. The implication of this conclusion is that future behavioural studies of social cognition will have considerable ethical and legal implications for animal welfare.

Abstract: Previous work (Marc et al., 2000) suggested that plasma cortisol responses to treadmill exercise or ACTH injection are a reliable marker for performance evaluation in warmblood horses. For practical purposes blood sample collections and treadmill exercise tests are somewhat troublesome and time consuming. The goal of this study was thus to evaluate the use of saliva for cortisol determination (by direct EIA) as a marker for performance and to investigate the reliability and repeatability of plasma cortisol responses to a single i.v. injection of ACTH (50 micrograms or 250 micrograms). Furthermore, the effect of training horses for 8 weeks 3 times per week covering the same distance (increasing from 3.5 km during the first week to 8 km during the last week) either by trotting (approximately 240 m/min) or by cantering (375 m/min) was investigated. For this purpose initially ten four-year-old Hannovarian geldings, all reared in the same State stud, were used. Mean overall correlation between salivary cortisol and plasma cortisol concentrations was 0.64 when samples of various points of time were used. However, in spite of attempts to standardize saliva sample collection, correlation between salivary cortisol levels and plasma cortisol levels at distinct points of time in different tests were low and significant (r = 0.85, p < 0.02) only in one test. Thus, salivary cortisol measurements for diagnostic purposes are not reliable or useful. The repeatability of plasma cortisol responses to ACTH for untrained and trained horses were r = 0.86 and r = 0.8 respectively (p < or = 0.01 and p < or = 0.05 respectively). Training horses either by trotting or cantering did not affect the cortisol response either to treadmill exercise or to stimulation by ACTH. It is concluded that the relationship between salivary cortisol levels and plasma cortisol levels is not close enough to allow the use of salivary cortisol determination as marker of the training status/fitness of horses. The repeatability of the cortisol response to ACTH is similar to the cortisol response to treadmill exercise. Based on plasma cortisol responses to ACTH or treadmill exercise training horses by cantering at low speed is not superior to training by trotting for the fitness of horses.