The Order of Movement of Yellow Baboons (<i>Papio cynocephalu</i><i>s</i>)

Abstract

The spatial organization of progressing baboons is thought to serve a protective function considered important in their adaptation to a terrestrial existence. Progression positions of identified black infants, adult males, and other yellow baboons were determined from repeated samples of troop movements. Spatial positioning by demographic class was similar to that previously found for three troops of anubis baboons living in two different habitats. Such consistency across species and habitats seems unlikely unless it arises from a common genetic background or common ontogenetic stabilizing mechanisms.

Adult Male Positioning in Baboon Progressions: Order and Chaos Revisited

“…One is a revision and extension of the protection theory [Rhine, 1975], taking into account variations due to experience and temperament, which were also stressed by Harding [1977], and resting on the central assumption of significant nonrandom tendencies in age-sex positioning. In a protective, nonrandom arrangement, the probability of exposing vulnerable troop members to danger should be less than the probability of exposing more self-sufficient ani mals.…”

“…In a protective, nonrandom arrangement, the probability of exposing vulnerable troop members to danger should be less than the probability of exposing more self-sufficient ani mals. The assumption of a single protective organization, such as central posi tioning of dominant males and vulnerable young, is not necessary; indeed, a protective spatial organization may reasonably be expected to shift in different settings [Rhine, 1975],…”

“…If tests of such proximate causes are negative, either the proximate theory must be convincingly revised or the entire theoretical structure will suffer. Rhine [1975] has suggested that the proximate 'roots of the order found in the midst of progression varia tion can be largely attributed to differences in fearfulness among demographic classes' (p. 97): In brief, the less fearful troop members should be more willing to occupy the fringes of moving troops, especially the front and rear, whereas more fearful animals should more often attempt to place others between them selves and possible danger and should be more careful about becoming too separated from the center of the troop's mass. Adult males should be the boldest troop members and therefore the most willing to take up positions in the ex posed front or rear of moving progressions.…”

“…If the protection theory of spatial organization is manifested proximally through fear or confidence, then repeated failure to disprove the implications of differential age-sex boldness bears at once on both the fear hypothesis and the protection theory. In addition to fear or confidence, other proximate factors in group life, such as consorting or interest in infants, may also influence progression order [Rhine, 1975].…”

“…Other quantitative studies had already stressed that no age-sex group always occupies any particular progression position [Harding, 1977;Rhine, 1975;Rowell, 1969], That DeVore and Washburn [1961aWashburn [ , 1963 had early recognized progression variations is illustrated by quotes from their work in a paper (Rhine [1975], p. 73) repeatedly cited in Altmann's [1979] article, which neither acknowledged the recognition of variation nor mentioned Harding's [1977, p. 352] relevant comment, as follows: 'With the advantage of hindsight it is easy to say that no group of mammals is likely to move as systematically as baboons were once thought to move, and indeed, according to Washburn [Per sonal commun. ], follow-up visits to Nairobi Park showed that even these baboons alter their behavior when entering different areas.…”