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: Urinary estrone conjugates (E1C), pregnanediol-3-glucuronide (PdG), and follicle-stimulating hormone (FSH) were determined by enzyme immunoassays (EIAs) during the normal menstrual cycle in the orangutan, gorilla, chimpanzee, and bonobo. Furthermore, the data were compared to those levels in the human and long-tailed macaque. The results showed a typical preovulatory E1C surge and postovulatory increase in PdG in all species. The pattern of E1C during the menstrual cycle in the great apes more closely resembled the human than do the long-tailed macaque. A major difference of E1C pattern between these species appeared in the luteal phase. In the great apes and the human, E1C exhibited two peaks, the first peak detected at approximately mid cycle and the second peak detected during the luteal phase. On the other hand, in the long-tailed macaque, increase of E1C in the luteal phase was small or nonexistent. The gorilla, chimpanzee, and bonobo exhibited similar PdG trends. The orangutan excreted one tenth less PdG than these species during the luteal phase. The long-tailed macaque also excreted low levels of PdG. The patterns of FSH in orangutan, chimpanzee, bonobo and long-tailed macaque showed a marked mid-cycle rise and an early follicular phase rise, similar to those in the human. Comparing similar taxa, a large difference was found in FSH of gorilla; there were three peaks during the menstrual cycle. Thus, there is considerable species variation in the excretion of these hormones during the menstrual cycle and comparative studies could be approached with a single method. The methods and baseline data presented here provide the basis for a practical approach to evaluation and monitoring of ovarian events in the female great apes.

Pigeons were trained to discriminate human facial expressions, happiness and anger, in a go/ no-go discrimination procedure. Five pigeons learned to discriminate photographs of the happy and angry faces of 25 different people and showed high levels of transfer to novel faces expressing the training emotions. The pigeons directed their pecks predominantly to the mouth, eyes, or the area between these features. The pigeons were then tested with familiar stimuli in which the upper and lower parts of the face were manipulated separately by substitution or removal of facial features (“eyes-and-eyebrows” and “mouth”). It was shown that the salience of particular features differed considerably among the birds, but that a linear feature model adequately accounted for discriminative performance of the birds with these stimuli. Furthermore, the discrimination was maintained when these features were inverted. Thus, the so-called Thatcher illusion did not occur. It is suggested that the discrimination is based not on a feature configuration or perceptual gestalt but on an additive integration of individual features.

Because of its close phylogenetic relation to human, great apes have subsequently attracted considerable interest in a wide range of research. However, their natural habitat was extensively destroyed and the number of wild living great apes now has decreased considerably and they are classified as endangered species. To prevent extinction of these species, assessing their reproductive status is indispensable. Non-invasive methods for monitoring reproductive status of great apes based on the measurement of urinary steroids and gonadotropins were examined. Urinary estrone conjugates (E1C), pregnanediol-3-glucuronide (PdG), and follicle-stimulating hormone (FSH) were determined by enzyme immunoassays (EIAs) during normal menstrual cycle in the orangutan, gorilla, chimpanzee, and bonobo. The data were compared to those levels in the human and long-tailed macaque. Moreover, urinary chorionic gonadotropin (CG) were measured during pregnancy in the chimpanzee. The results showed a typical preovulatory E1C surge and postovulatory increase in PdG in all species. The pattern of E1C during the menstrual cycle in the great apes more closely resembled the human than do the long-tailed macaque. A major difference of E1C pattern between these species appeared in luteal phase. In the great apes and the human, E1C exhibited two peaks, the first peak detected at approximately midcycle and the second peak detected during the luteal phase. On the other hand, in the long-tailed macaque, increase of E1C in luteal phase was small or nonexistent. The gorilla, chimpanzee, and bonobo exhibited similar PdG trends. The orangutan excreted 1:10 less PdG than these species during the luteal phase. The long-tailed macaque also excreted low levels of PdG. The patterns of FSH in orangutan, chimpanzee, bonobo and long-tailed macaque showed a marked midcycle rise and an early follicular phase rise, and similar to those in the human. Comparing the similar taxa, a large difference was found in FSH of gorilla. There were three peaks of FSH during the menstrual cycle in the gorilla. Thus, there is considerable species variation in the excretion of these hormones during menstrual cycle and that comparative studies could be approached with a single method. The earliest changes indicating pregnancy were a coincident rise in E1C and chorionic gonadotropin (CG) levels and a concomitant fall in FSH levels. Urinary PdG levels showed a prolonged rise. Urinary E1C in the pregnant chimpanzee was higher than during the menstrual cycle and increased with advancing gestation, with maximum levels occurring near term. The methods and baseline data presented here provide the basis for a practical approach to evaluation and monitoring of reproductive events in the female great apes. (poster)