Abstract: We investigate models for animal feeding behaviour, with the aim of improving understanding of how animals organise their behaviour in the short term. We consider three classes of model: hidden Markov, latent Gaussian and semi-Markov. Each can predict the typical `clustered' feeding behaviour that is generally observed, however they differ in the extent to which `memory' of previous behaviour is allowed to affect future behaviour. The hidden Markov model has `lack of memory', the current behavioural state being dependent on the previous state only. The latent Gaussian model assumes feeding/non-feeding periods to occur by the thresholding of an underlying continuous variable, thereby incorporating some `short-term memory'. The semi-Markov model, by taking into account the duration of time spent in the previous state, can be said to incorporate `longer-term memory'. We fit each of these models to a dataset of cow feeding behaviour. We find the semi-Markov model (longer-term memory) to have the best fit to the data and the hidden Markov model (lack of memory) the worst. We argue that in view of effects of satiety on short-term feeding behaviour of animal species in general, biologically suitable models should allow `memory' to play a role. We conclude that our findings are equally relevant for the analysis of other types of short-term behaviour that are governed by satiety-like principles.

Abstract: Delayed-responses have been traditionally employed to investigate the temporal characteristics of animals“ ability to represent and recall objects that have disappeared. In the typical condition, the animal, usually a mammal, observes the experimenter hiding an interesting goal (e.g. some food) in a certain location. A delayed-response task (DRT) was administered to 4 female Esperia pony (2 years old) coming from a free-range breed (Frosinone, Italy) and to 7 female Amiata donkeys (4.2±2 years old) coming from a conservation stock (University of Pisa, Italy). The DRT's apparatus was located in a square fence. A single ”U-shaped“ screen (330x160x140 cm) made by wood shavings blocks was positioned in the centre of the fence. A gap (40x50 cm) on the ground was in the middle of the central side of the U-shaped-screen and served to make the food-attractor disappear. The food-attractor consisted in cereal flakes and fresh grass for ponies and cereal flakes for donkeys. A bucket full of food was placed on a dolly tied on a rope which could be pulled by an experimenter. In a preliminary training each animal was allowed to eat food from the bucket and, while the animal was eating, the dolly was gently pulled away from the animal, and beyond the screen through the gap. The subjects needed to move around of the screen in order to retrieve the food. As a reinforcement, they were allowed to eat some food from the bucket once behind the screen. From trial to trial, the bucket was presented farther and farther (starting with a distance of 1 m in front of the screen to reach 7 m). Therefore subjects were tested in the DRT requiring them to rejoin the bucket with the goal-food disappearing behind the screen as in the preliminary training but following a 10 s delay. For the DRT, the bucket was placed 7 m in front of the screen, 3 m away from the animal's starting area. Then the dolly was pulled away from the animal. Ten seconds after the disappearance of the dolly behind the screen the animal was released from the starting area. The DRT ended when the subject had reached the attractor behind the screen on 3 consecutive trials. Results showed that all animals were able to rejoin the food behind the screen after 10 s delay. The mean time of the delayed-response (mean±sd, in s) in the ponies (1st: 19.8±8; 2nd: 10.8±2.2; 3rd: 12.8±2.8) and in the donkeys (1st: 28.4±10; 2nd: 26.9±13; 3rd: 24.3±16.6) showed a trend to decrease from first trial to third. These preliminary results suggest that like other mammals our ponies and donkeys can maintain a working memory trace of the location where biologically attractive objects have been seen to disappear. In conclusion, this study paves the way to set up a viable model system for the investigation of the more sophisticated aspects of Equids” cognitive abilities such as working memory.

Abstract: A wide variety of maternal, social and sexual bonding strategies have been described across mammalian species, including humans. Many of the neural and hormonal mechanisms that underpin the formation and maintenance of these bonds demonstrate a considerable degree of evolutionary conservation across a representative range of these species. However, there is also a considerable degree of diversity in both the way these mechanisms are activated and in the behavioural responses that result. In the majority of small-brained mammals (including rodents), the formation of a maternal or partner preference bond requires individual recognition by olfactory cues, activation of neural mechanisms concerned with social reward by these cues and gender-specific hormonal priming for behavioural output. With the evolutionary increase of neocortex seen in monkeys and apes, there has been a corresponding increase in the complexity of social relationships and bonding strategies together with a significant redundancy in hormonal priming for motivated behaviour. Olfactory recognition and olfactory inputs to areas of the brain concerned with social reward are downregulated and recognition is based on integration of multimodal sensory cues requiring an expanded neocortex, particularly the association cortex. This emancipation from olfactory and hormonal determinants of bonding has been succeeded by the increased importance of social learning that is necessitated by living in a complex social world and, especially in humans, a world that is dominated by cultural inheritance. © 2006 The Royal Society.

Abstract: Numerous previous investigators have explained species differences in spatial memory performance in terms of differences in foraging ecology. In three experiments we attempted to extend these findings by examining the extent to which the spatial memory performance of echidnas (or “spiny anteaters”) can be understood in terms of the spatio-temporal distribution of their prey (ants and termites). This is a species and a foraging situation that have not been examined in this way before. Echidnas were better able to learn to avoid a previously rewarding location (to “win-shift”) than to learn to return to a previously rewarding location (to “win-stay”), at short retention intervals, but were unable to learn either of these strategies at retention intervals of 90 min. The short retention interval results support the ecological hypothesis, but the long retention interval results do not.

Abstract: We presented bumblebees a spatial memory task similar to that used with other species (e.g., cats, dogs, and pigeons). In some conditions we allowed for presence of scent marks in addition to placing local and global spatial cues in conflict. Bumblebees (Bombus impatiens) were presented an array of artificial flowers within a flight cage, one flower offering reward (S+), while the others were empty (S-). Bees were tested with empty flowers. In Experiment 1, flowers were either moved at the time of testing or not. Bees returned to the flower in the same absolute position of the S+ (the flower-array-independent (FAI) position), even if it was in the wrong position relative to the S- and even when new flower covers prevented the use of possible scent marks. New flower covers (i.e., without possible scent marks) had the effect of lowering the frequency of probing behavior. In Experiment 2, the colony was moved between training and testing. Again, bees chose the flower in the FAI position of the S+, and not the flower that would be chosen using strictly memory for a flight vector. Together, these experiments show that to locate the S+ bees did not rely on scent marks nor the positions of the S-, though the S- were prominent objects close to the goal. Also, bees selected environmental features to remember the position of the S+ instead of relying upon a purely egocentric point of view. Similarities with honeybees and vertebrates are discussed, as well as possible encoding mechanisms.