Pileated gibbons (Hylobates pileatus) are rated as endangered according to the International Union of Conservation of Nature (IUCN) Red List. The captive population suffers from poor breeding success and is threatened to become overaged. Although several factors are likely to contribute to the poor breeding success, one in particular may be chronic stress associated with prolonged periods of high glucocorticoid (GC) output. We investigated fecal GC levels of pileated gibbons (Hylobates pileatus) and their relationship to specific life-history variables and environmental factors. After validation of an enzyme immunoassay for the measurement of 5-reduced 3α,11β-dihydroxy cortisol metabolites to assess GC output reliably in pileated gibbons, we collected fecal samples over several days from all 36 European adult pileated gibbons located in 11 institutions and compared Int GC levels to intrinsic individual parameters, husbandry, behavior, and breeding history. Age, sex, and origin (wild vs. captive born) had no effect on GC levels. However, unnaturally reared gibbons had higher GC levels and showed more behavioral abnormalities than parent-reared individuals. Further, nonreproducing gibbons living in a pair without infants had higher GC concentrations than gibbons living in a family, bachelor group, or as singletons. With respect to environmental factors, a large size of the inside enclosure and the existence of visual protection from visitors was associated with lower fecal GC output. The data indicate that rearing and housing conditions appear to correlate to GC levels in pileated gibbons housed under captive conditions. It is hoped this knowledge will support the future management of the species in captivity and thus lead to a more successful breeding of this endangered primate.

Three experiments modeled after infant studies were run on four great ape species (Gorilla gorilla, Pongo pygmaeus, Pan troglodytes, Pan paniscus) to investigate their reasoning about solidity and gravity constraints. The aims were: (a) to find out if great apes are subject to gravity biased search or display sensitivity for object solidity, (b) to check for species differences, and (c) to assess if a gravity hypothesis or more parsimonious explanations best account for failures observed. Results indicate that great apes, unlike monkeys, show no reliable gravity bias, that ape species slightly differ in terms of their performance, and that the errors made are best explained by a gravity account.Keywords: invisible displacement, object solidity, gravity error, naïve physicsVarious constraints, such as gravity, inertia, or solidity, act upon a moving object, shaping its pathway through time and space. To locate an invisibly displaced object, an infant must have some knowledge of how these constraints interact to determine the future trajectory of the object moving out of sight (Baillargeon,

Results suggest a higher importance of individual factors for the development of URTD than environmental conditions. Bornean, male and hand-reared orangutans and animals related to diseased animals need increased medical surveillance for early detection of respiratory disease.

Plains viscachas (Lagostomus maximus) are large South American, fossorial rodents susceptible to diabetic cataracts. Various aspects of their digestive physiology were studied in three different experiments with 9 male and 7 female adult animals and 6 different diets (total n of feeding trials = 35). Viscachas achieved mean retention times of 23-31h, which is of a magnitude also recorded in horses; these did not differ for solute or small particle (<2mm) markers. Secondary marker excretion peaks indicated coprophagy, and were rarer on high-protein as compared to grass hay-only diets. Mean resting metabolic rate was, at 229 kJ/kg0.75/d, lower than expected for a mammal of this size. Digestible energy requirement for maintenance was 445 kJ/kg0.75/d. At 1.6-2.7 L/d, viscachas produced more methane than expected for a hindgut fermenter of their size. On diets that included concentrate feeds, viscachas excreted glucose in their urine, corroborating reports on the susceptibility of this species for diabetes when kept on energy-dense food. Viscachas had a similar apparent digestibility of protein, lipids, and macrominerals as other rodents, rabbits, or domestic horses. This suggests that whether or not a species practices coprophagy does not have a major influence on these measures. Viscachas resemble other hindgut fermenters in their high apparent calcium digestibility. With respect to a digestibility-reducing effect of dietary fiber, viscachas differed from rabbits and guinea pigs but were similar to horses, suggesting that small body size needs not necessarily be linked to lower digestive efficiency on high-fiber diets. three different experiments with 9 male and 7 female adult animals and 6 different diets (total 28 n of feeding trials = 35). Viscachas achieved mean retention times of 23-31h, which is of a 29 magnitude also recorded in horses; these did not differ for solute or small particle (<2mm) viscachas excreted glucose in their urine, corroborating reports on the susceptibility of this 36 species for diabetes when kept on energy-dense food. Viscachas had a similar apparent 37 digestibility of protein, lipids, and macrominerals as other rodents, rabbits, or domestic 38horses. This suggests that whether or not a species practices coprophagy does not have a 39 major influence on these measures. Viscachas resemble other hindgut fermenters in their high 40 apparent calcium digestibility. With respect to a digestibility-reducing effect of dietary fiber, 41 viscachas differed from rabbits and guinea pigs but were similar to horses, suggesting that 42 small body size needs not necessarily be linked to lower digestive efficiency on high-fiber 43 diets. 44 45

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