Abstract: The effect of short periods of strenuous exertion, in this case treadmill exercise, on the subsequent behavior of Standardbred horses was examined. Six horses were exercised on a high-speed treadmill 4 or 5 days per week, for 3-4 miles (approximately 1.8 m s-1 for 3 min, 5 m s-1 for 12 min, 9 m s-1 for 3 min, 3 m s-1 for 3 min, 1.8 m s-1 for 3 min). The behavior of the horses was observed in the horse's home stall immediately after exercise and 2-7 h after exercise. Focal animal sampling for a total of 150 h revealed that the horses spent significantly more time drinking and less time resting after exercise than they did on control (non-exercise or rest days). The greatest influence on behavior was seen immediately after exercise. The horses spent 13.2+/-2.7 s per 15 min drinking after exercise and 7.2+/-2.3 s per 15 min drinking on non-exercise days. They spent 7.3+/-1.5 min h-1 stand resting after exercise and 9.7+/-2.1 min h-1 on non-exercise days. These changes in behavior may be related to the physiological changes that accompany exercise. Eating, walking, elimination and self-grooming were not significantly influenced by exercise. In a second experiment the activities of two groups of six Standardbred mares were compared. One group was exercised on the treadmill and the other was not. The exercised horses spent more time drinking and lying, but urinated less than the non-exercised group.

Abstract: Foragers can often show a broad range of strategies when searching for resources. The simplest foraging strategy is to search randomly within a habitat; however, foragers can often assess habitat quality over various spatial scales and use this information to keep themselves in, or direct themselves to, regions of high resource abundance or low predation risk. We investigated models that describe a population of consumers competing for a renewable resource that is distributed among discrete patches. Our aim was to identify what foraging strategy or strategies are expected to persist within a population, where strategies differ in the degree of habitat assessment (i.e. none, local, or global). We were interested in how the optimal strategies are dependent on the cost of assessment and habitat structure (i.e. the variation in renewal rates and predation risks among patches). The models showed that the simple random foraging strategy (i.e. make no habitat assessments) often persisted even when the cost of habitat assessment was low. Persistence could occur when habitat assessment and population dynamics generated an ideal free distribution because it could be exploited by the random foragers. Habitat assessment was more advantageous when consumers could not achieve ideal free distributions, which was more likely as patches became less productive. When productivity was low we sometimes observed the situation where different foraging strategies generated resource heterogeneities that promoted their coexistence, and this could occur even when all patches were intrinsically identical.

Abstract: Summary Three groups of eight female golden hamsters without prior breeding experience were presented with three newborn pups for a 15 min test period. Group V were virgin females, group P pregnant females and group L lactating females. Groups P and L were tested within 24 hr of parturition. Group V attacked and killed all pups presented. Group P showed maternal responses after initial attacks while group L accepted the pups. Groups P and L did not differ significantly on measures of maternal responsiveness but all three groups differed significantly from one another on measures of attacking behaviour and the eating of young.