Summary: Ulyan et al. (2006)

Ulyan et al. (2006) evaluated the responses of group living capuchins (Cebus apella) to different feeding schedules. They fed animals a predictable schedule for 6 weeks, then an unpredictable schedule for another 6 weeks. They sampled behaviour using scan sampling (1 minute intervals) for 1 hour pre- and post-feed. Ulyan et al. (2006) hypothesized that behaviour and faecal cortisol concentration would be influenced by meal unpredictability. They did not find any major differences in behaviours typically associated with stress or anticipation, but suggest that differences in other behavioural measures indicates that predictable feeding regimes is better for the animals' well being. Their results suggest that the anticipation of feeding is pronounced when feeding time is delayed in an unpredictable manner and cortisol concentration increases during this time. Ulyan et al. (2006) propose that a predictable feeding schedule is more beneficial for the well being of captive capuchins.

Summary: Chapuis & Bshary (2010)

Signals alter the behaviour of receivers, thereby increasing the sender's fitness. When individuals interact cooperatively, signal strength may be linked to supply and demand (biological market theory). Hunger level in cleaner shrimps (Periclimenes longicarpus) is linked to advertisement of their services to client reef fish. To test more detailed predictions of biological market theory, Chapuis & Bshary (2010) investigated signalling by wild cleaner shrimps. Shrimps increased claw clapping when they were food deprived and were more likely to clean than non-clapping shrimp. Chapuis & Bshary (2010) however did not find evidence that signalling was target-specific to visiting client species, and shrimps signalled more frequently to predatory species. They conclude that signal conveys information about identity in order to avoid predation, rather than to attract choosy clients.

Summary: Stetina et al. (2011)

Recognition of emotions is required for interpersonal interactions and emotional competencies. Stetina et al. (2011) explored the possibility of enhancing emotion recognition of children (5-7 years) and adults (19-45 years) by using animal-assisted intervention, focusing on the emotional expression of dogs. Their results showed that the highest changes in both the adult and children groups related to the correct identification of fear and anger. Adults also showed an increase in the overall number of correctly identified facial expressions, as well as a decrease in the latency to respond. Children also increased their capacity for the recognition of disgust and neutral facial expressions, identified 5 more emotions correctly after training and decreased their response latency. Stetina et al. (2011) suggest that a generalization process from human-dog interaction to human-human interaction seems to occur. They indicate that the implied learning effects of animal-assisted interventions are a promising and essential aspect of psychological and psychosocial treatment.

Summary: Townsend & Moger (1987)

Male Puerto Rican frogs Eleutherodactylus coqui are paternal throughout embryonic development of the eggs. Males stop calling (which is necessary for attracting mates) and reduce egg cannibalism during this period. Townsend & Moger (1987) analyzed the relationship between parental behaviour and androgens by analysing blood plasma from males captured in the field. They found that paternal males had lower androgen levels than males that were nonpaternal, calling or amplectant. They noted that the decline in circulating androgens between the sexually active state and the paternal care state was rapid, but also that androgen levels did not differ between males that were at differing stages of the paternal care period. Townsend & Moger's (1987) results suggest a relationship between circulating androgen levels, mating behaviour and the development of paternal care.

Summary: Wainwright et al. (1999)

Linoleic acid and alpha-linoleic acid can not be synthesized by animals and must be obtained through their diet. These fatty acids are important for essential for growth and development. Wainwright et al. (1999) compared behavioural development of young born to female B6D2F1 mice that had been fed a diet with an imbalance of dietary essential fatty acids to pups that had been undernourished (through rearing in large litters). Some pregnant and lactating females were fed a diet with a very low (n-6):(n-3) ratio, in which the fatty acids were provided solely as linoleic acid and very high levels of docosahexaenoic acid. Wainwright et al. (1999) randomly established four groups of females : 2 groups were fed lab chow but varied in litter size (large vs. normal), and 2 groups were of normal litter size but varied in dietary ratio (low=0.32 vs. normal = 4.0). At 32 days post conception, offspring from both lab chow-fed large litters and low ratio normal litters had lower body weights and were behaviourally retarded. Wainwright et al.'s (1999) results show that growth retardation (offspring of dams fed a diet with low essential fatty acid ratio and very high levels of DHA) is accompanied by behavioural retardation similar to that seen in malnourished pups.