Stuart A. Altmann

Life History of Yellow Baboons: Physical Development, Reproductive Parameters, and Infant Mortality

Longitudinal data from a population of yellow baboons,Papio cynocephalus, in the Amboseli National Park, Kenya, provide life history parameter estimates. Females reached menarche at approximately four-and-a-half years of age and then cycled for approximately a year before first conception. Postpartum anestrum averaged 12 months but ranged from six to 16 months. In cases of still births or infant death during postpartum amenorrhea, females commenced cycling after approximately one month. In mature females the time spent cycling before conception was five months on the average with a range from one to over 18 months. Only half of all full-term pregnancies resulted in infants who survived the first year of life; only a third, in infants who survived until the birth of their mother’s next infant. In comparison with data from laboratory colonies, our data indicate that female baboons in Amboseli are older at birth of first infant. They have, on the average, a somewhat shorter interbirth interval than was estimated from earlier crossectional field data, and therefore spend a larger portion of their adult life pregnant, but have a much longer interval—at least three years on the average—between the birth of an infant and the birth of that infant’s next older surviving sibling. A number of morphological changes in immature baboons are described.

Long-Term Consistency of Dominance Relations Among Female Baboons (Papio cynocephalus).

At maturity, female baboons in the Amboseli National Park of Kenya generally attain a rank position among adults near to that of their mothers. However, the age of a females mother and the difference in ages between sisters also influence the rank acquisition process. These latter demographic variables, which are sensitive to changes in resource availability, may account for the close association both within and among primate species of specific patterns of rank organization and specific environmental conditions.

Two models for the evolution of polygyny

SummaryTwo models of conditions for the evolution of polygyny are treated axiomatically. Both models assume a social system based on female mate choice in situations in which a female is better off if she mates polygynously with an already mated male on a superior territory than if she selects a bachelor on an inferior territory. One model, the competitive female choice model, assumes that the females of a harem compete for the limited resources of the harem and thus that their fitness decreases as co-wives are added. The cooperative female choice model assumes that, within limits, a females fitness is improved by the addition of co-wives to her mates harem, as a result of cooperative interactions within the group. For each model, a sufficient set of independent assumptions is provided. Implications of the models are indicated and methods for testing them are discussed.

Resource base, parity, and reproductive condition affect females' feeding time and nutrient intake within and between groups of a baboon population

SummaryWe examined within- and between-group differences in aspects of feeding and nutrient intake among adult females of a single population of baboons (Papio cynocephalus) in Amboseli National Park, Kenya. Differences in time spent feeding, daily energy and protein intake and feeding efficiency (nutrient intake per minute spent feeding) reflected differences in resource base, reproductive condition and parity. Baboons that partially fed from a lodge garbage dump spent less than half the time feeding than those that were feeding totally in the wild. During this greatly reduced feeding time, the garbage-feeding group had a similar daily energy intake and only a slightly lower daily protein intake relative to wild-feeding baboons. Consequently, the feeding efficiency of the semi-provisioned baboons was appreciably higher than that of the non-provisioned baboons. For the totally wild-feeding baboons, samples were large enough to permit analyses of feeding time and nutrient intake during different reproductive states and parity. Females spent more time feeding and had higher daily energy and protein intake when they were pregnant or lactating than when they were sexually cycling. Nulliparous females spent more time feeding than their multiparous counterparts. The daily energy intake of nulliparous females was higher than that of their multiparous counterparts, but their daily protein intakes did not differ significantly. Pregnant or lactating and nulliparous females had higher feeding efficiency than their sexually cycling and multiparous counterparts. The two nulliparous females in the garbage-feeding group spent more time feeding but did not take in more energy or protein per day than their multiparous counterparts.

On the analysis of rates of behaviour

Formulas are developed for calculating the expected frequency of behaviour and of social interactions in each age-sex category or other class, particularly when the study population changes composition during the study, given the null hypothesis either of constant but unknown rates of behaviour that are independent of class, or of class-specific rates per individual.

The transformation of behaviour field studies

As areas of science mature, they pass through three, broadly overlapping stages of development, characterized respectively by description, explanation and synthesis. Field research on animal behaviour is making the transition from an area with a preponderance of purely descriptive studies to one that also includes the development and testing of verifiable hypotheses about the structure, causes and consequences of behaviour. We survey several reasons for this transformation of behaviour field studies and some of the major trends that characterize it, including: (1) patterns discerned in our cumulative knowledge of natural history; (2) increased support for behaviour field studies; (3) interfaces with related areas of science; (4) the development of observational sampling methods and other aspects of data sampling and analysis; (5) the development of models of behaviours adaptive functions and life-history consequences; (6) long-term field sites that make possible complete life histories, increased attention to individual differences and intergenerational studies of behaviour; and (7) the development of techniques for remote tracking of animals and for noninvasive, hands-off sampling of a range of behavioural, physiological, genetic and environmental phenomena. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.

Baboon progressions: Order or chaos? A study of one-dimensional group geometry

Abstract Baboon progressions were sampled in Africa during 1963–1972. Contrary to numerous speculations, there was no invariable progression order, either by individual or by age-sex class. Indeed, most progression orders were essentially random. In the few deviant cases, usually in dangerous situations, juveniles and adult males were over-represented in the fron third, adult males in the last third. Small infants were usually next to their mother, large ones next to each other. Deviations probably result primarily from residual effects of pre-progression social groupings, sometimes combined with differential roles in group co-ordination, and shifts in position, including male peripheralization, when baboons are faced with danger. Statistical techniques for analysis of group geometry are discussed. Some are insensitive to subtle spatial patterns.

Fallback Foods, Eclectic Omnivores, and the Packaging Problem

For omnivorous primates, as for other selective omnivores, the array of potential foods in their home ranges present a twofold problem: not all nutrients are present in any food in the requisite amounts or proportions and not all toxins and other costs are absent. Costs and benefits are inextricably linked. This so-called packaging problem is particularly acute during periods, often seasonal, when the benefit-to-cost ratios of available foods are especially low and animals must subsist on fallback foods. Thus, fallback foods represent the packaging problem in extreme form. The use of fallback foods by omnivorous primates is part of a suite of interconnected adaptations to the packaging problem, the commingling of costs and benefits in accessing food and other vital resources. These adaptations occur at every level of biological organization. This article surveys 16 types of potential adaptations of omnivorous primates to fallback foods and the packaging problem. Behavioral adaptations, in addition to finding and feeding on fallback foods, include minimizing costs and requirements, exploiting food outbreaks, living in social groups and learning from others, and shifting the home range. Adaptive anatomical and physiological traits include unspecialized guts and dentition, binocular color vision, agile bodies and limbs, Meissners corpuscles in finger tips, enlargement of the neocortex, internal storage of foods and nutrients, and ability internally to synthesize compounds not readily available in the habitat. Finally, during periods requiring prolonged use of fallback foods, life history components may undergo changes, including reduction of parental investment, extended interbirth intervals, seasonal breeding or, in the extreme, aborted fetuses.

WHAT TIME DO THE BABOONS COME DOWN FROM THE TREES? (AN ESTIMATION PROBLEM)

SUMMARY We consider a system that can be in either of two observable states, that begins each day in the first state, and exactly once each day makes a transition to the second state. An observer records the time of transition on a number of days, but on certain other days arrives too late to witness the transition. On those days he can only say that the transition occurred sometime earlier than his arrival time. We show how to use all the available data to obtain an unbiased estimate of the distribution of transition times. 1. PROBLEM

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