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Direct eye contact may function as a warning cue during interspecific interactions, and human staring has been shown to influence the behavior of many species. The authors used an arena test to assess whether human staring altered the behavior of domestic sheep (Ovis aries) compared with no human eye contact. Sheep glanced at the staring human's face more often in the first 2 min of the test, indicating that they perceived a difference between the human stimuli. Staring also elicited more locomotor activity and urination than averted gaze. However, there were no differences in fear-related behaviors, suggesting that a staring human did not represent a greater immediate threat than a nonwatching human. These results imply that human staring is a warning cue for domestic sheep, but no more. Without further reinforcement, sheep quickly habituated to the warning cue., (((c) 2006 APA, all rights reserved).)

We examined the physical properties of digesta from the proximal (sacciform) and distal (tubiform) regions of the forestomach of tammar and parma wallabies maintained on a ryegrass sward. The digesta exhibited high viscosity, which, in conjunction with low flow rates calculated from published retention times of particulate marker in the stomach, results in a low potential for macrofluid mixing during onflow of food by displacement. The pseudoplastic nature of the viscosity profile and very low "flow behavior index" also indicate that macrofluid mixing around haustrae would be very localized. These findings indicate that the uniform mixing of whole digesta required for continuously stirred tank reactors (CSTRs) is unlikely. Voidage, the proportion of digesta not occupied by solid material, and "consistency index" were greater in the digesta from the proximal than in the distal regions of the forestomach. We conclude that the mixing conditions in wallaby stomachs are better described as a partially emptying batch reactor (PEBR) than a CSTR series and that lower permeabilities in conjunction with higher viscosities decrease axial mixing and thus increase efficiency in PEBRs.