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When problem based learning occurs in a social context it is open to a common social behaviour, scrounging. In the animal behaviour literature, scroungers do not attempt to find resources themselves but rather exploit resources found by other group members (referred to as producers). We know from studies of animal behaviour (including humans) that scrounging can be expected whenever animals exploit resources in groups. We also know that scrounging can have deleterious effects on the group. We can expect scrounging to occur during social learning because the exchange of information (which I will consider here as a resource) is essential to social learning. This exchange can be seen as each individual scrounging from the other members of the group whenever the individual learns from the work of others. However, there is a danger if some individuals learn mostly through their own efforts while others indulge in "social loafing" relying heavily on colleagues to provide knowledge. Here I propose that game theory models developed to analyse feeding in animal societies may also apply to social learning. We know from studies of birds feeding in groups that scrounging behaviour depends on the extent to which resources can be shared. Further, when scrounging is prevalent groups tend to obtain fewer resources. By contrast, in social learning we attempt to facilitate sharing of knowledge. We thus encourage scrounging and run the risk of reducing learning within study groups. Here I analyse the role of scrounging in problem based learning. I argue that scrounging is inherent and necessary to any social learning process. However, it can have perverse effects if the acquisition of facts rather than understanding comes to dominate learning objectives. Further, disparities among individuals within a group can lead certain individuals to specialise in scrounging thus undermining the functioning of the group. I suggest that motivation, problem structure, discussion group dynamics, attention to results expected from students and careful evaluation can be used to encourage scrounging as a cooperative tactic while minimising its negative impacts on group "performance."

Studies on energy and protein acquisition's influence on rodent's choice of food revealed that a prey's inclusion in a diet is independent of its encounter rate and ranked only on a profitability basis. Deer mice prefer energy rich food, followed by low-protein food, though consumption quantity of both is equal. Protein rich food is rarely taken. These results show that deer mice do not choose their diet optimally because protein-poor food leads to weight loss and higher mortality.

This study tests five mechanisms for the coexistence of red squirrels (Tamiasciurus hudsonicus) and eastern chipmunks (Tamias striatus). These mechanisms, based on optimal foraging theory, depend on differences between the two species in habitat over space and time. The mechanisms are related to: 1) habitat; 2) microhabitat; 3) foraging and travel costs; 4); seasonal variation in predation risk; and 5) seasonal variation in thermoregulatory costs. Each speciesi foraging efficiency was estimated, using GUDs (Giving-up-densities) from February to July 1995 at the Morgan Arboretum, Ste. Anne-de-Bellevue, Quebec, Canada. GUDs were measured in 36 aluminum seed trays, each containing 20g of sunflower seeds, mixed with 2.25 l of kiln dried sand. Trays were set in three habitats (coniferous, deciduous and mixed forest), separated by at least 300 m with 6 pairs of trays per habitat. In general, the chipmunk was more efficient (left lower GUDs) than the red squirrel. The red squirrel was more efficient than the chipmunk in the coniferous forest during the spring and had exclusive access to food during the winter when the chipmunk was in hibernation. The chipmunk was the more efficient forager in the mixed forest in both spring andsummer. This spatio-temporal trade-off in foraging efficiency constitutes a mechanism which can promote coexistence between these two diurnal rodents. [ABSTRACT FROM AUTHOR]