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The intestinal protozoan faunas of 11 social groups of Cercocebus albigena, 3 groups of Ceropithecus mitis, 3 groups of Cercopithecus ascanius, 2 groups of rain forest and 4 groups of savannah Papio anubis are documented. All individuals in a particular social group exhibit identical protozoan faunas. All social groups of each species, except the savannah P. anubis, exhibit intergroup differences in the composition of their protozoan faunas. The number of intestinal, protozoan species in Cercocebus albigena social groups is a function of group size. The similarity between the protozoan faunas of different C. albigena groups is related to the density of the social groups and types of land tenure in particular localities. Past social history of C. albigena groups may have some influence on the level of similarity of different groups' faunas. Entrance of a nongroup member into a group of Cercopithecus mitis resulted in an increase in the species richness of the group's protozoan fauna. Group fission may result in reduction of a group's protozoan species richness. All groups of savannah Papio anubis exhibit identical protozoan faunas. I argue that this is because savannah P. anubis has a higher rate of exchange of individuals between groups than has been recorded for the rain forest primates under consideration. I hypothesize that the differing rates of exchange are due to disease—related selection against traits which result in high rates of individual exchange among rain forest primate groups. Primate social groups are functionally biological islands; the species of their protozoan faunas changes according to group size and levels of protozoan migration between groups.

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Due to the structure of the vegetation in Kibale Forest, Uganda, mangabeys (Cercocebus albigena) cannot avoid, and do not try to avoid, defecating on vegetation they may subsequently use in normal feeding and movement activities. Mangabeys defecate throughout the day. Sleeping areas are major sites of fecal contamination. Wet weather removes fecal contamination from leaves within 24 h. Dry weather results in live intestinal protozoa persisting in feces for more than 24 h. Mangabeys were found to travel further, use more area and exhibit less day—to—day overlap in use of area during dry weather than on days of rain. The data suggest that differences in movement and activity on days of rain and no rain are not due to observational error, or to mangabeys' movement being inhibited by rain. I suggest that the difference is due to rain removing fecal contamination from the environment. This allows concentrated use of areas during periods of rain. During dry weather, mangabeys move long distances and use more area, apparently to avoid environmental contamination, and thus frequently encounter rare food items such as fig tress in fruit. Food density could not be shown to influence mangabey use of areas within the home range.

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Recently metamorphosed Bufo marinus exhibit patterns of activity and habitat use that vary in relation to changes in weather and moisture availability. Activity adjacent to water is greatest on moist substrates at high daytime temperatures in windy weather. Conditions that inhibit evaporative cooling (no wind, dry substrates, high humidity), or are likely to lead to low body temperatures (cool temperatures at night under windy conditions) restrict activity. Activity in habitats away from permanent water is dependent on metamorphlings having grown large enough to allow night-time activity on dry substrates. Growth leads to a change in activity from diurnal as metarnorphlings, to nocturnal and diurnal as juveniles (30-70 mm SVL), and to nocturnal as adulthood approaches. Size-dependent changes in patterns of activity and habitat use are accompanied by changes in pelvic patch morphology and body pigmentation. The morphological changes may have resulted from selection acting to minimise time spent in the smaller size classes which are vulnerable to predators, competitors and the environment, and size-dependent optimisation of chemical defences.

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