Standardized descriptions of primate locomotor and postural modes

Abstract

ABSTRACT. As quantitative studies on primate positional behavior accumulate the lack of a standard positional mode terminology is becoming an increasingly serious deficiency. Inconsistent use of traditional terms and inappropriate conflation of mode categories hamper interspecific and interobserver comparisons. Some workers use common terms without definition, allowing at least the possibility of misunderstanding. Other researchers coin neologisms tailored to their study species and not clearly enough defined to allow application to other species. Such neologisms may overlap, may completely encompass, or may conflate previously defined labels. The result is, at best, the proliferation of synonyms and, at worst, the creation of confusion where clarity had existed. Historical precedents have sometimes resulted in "catch-all" terms that conflate any number of kinematically different behaviors (e.g. "brachiation," "climbing," and "quadrumanous climbing"). We recognize three areas where distinction of positional modes has some current importance: (1) Modes that require humeral abduction should be distinguished from adducted behaviors; (2) locomotor modes that involve ascent or descent should be distinguished from horizontal locomotor modes; and (3) suspensory modes should be distinguished from supported modes. We recommend a nomenclature that is not dedicated to or derived from any one taxonomic subset of the primates. Here we define 32 primate positional modes, divided more finely into 52 postural sub-modes and 74 locomotor sub-modes.

Locomotion and postural behaviour

“…Classifications of locomotor behaviour have occupied generations of scientists over the last century (Ashton and Oxnard, 1964;Mollison, 1910;Napier and Napier, 1967;Napier and Walker, 1967;Rollinson and Martin, 1981;Rose, 1973;Hunt et al, 1996). Both the most influential and the most controversial classification was proposed by Napier and Napier (1967), who divided the spectrum of primate locomotor modes into four discrete categories: quadrupedalism, vertical clinging and leaping, brachiation, and bipedalism.…”

“…However, postures only form a minor part of the activities performed by a primate besides locomotion. Over the past years, some effort has been made to find an ordering system for postural behaviours (Fontaine, 1990;Hunt et al, 1996) but other activities have hardly been considered (Ripley, 1967;Rose, 1977). Therefore, neither the evolutionary history of non-locomotory behaviours nor the potential relationship between morphology and these kinds of motor function have yet been investigated in any kind of detail.…”

Origin of human bipedalism: The knuckle-walking hypothesis revisited

“…Thus, the term "antipronograde" was coined (Stern, 1975) in an attempt to better describe the body posture, often Ͼ45°from horizontal, used by great apes (especially the orangutan) while moving in trees. The less cumbersome term "climbing" will be used here to indicate these kinds of vertical climbing and orthograde clambering behaviors, described in more detail in Hunt et al (1996).…”

Rain forests and movement ecology of neotropical primates

“…Demes, Fleagle ,Jungers 1999, Dunbar et al 2004, Jurmain 2000, Larson et al 2001, Malina & Little 2008, Maclatchy 1996, and decades of study have explored links between forest resources and the movements of common primates in Central American rain forests (e.g. Bezanson 2009, Estrada & Coates-Estrada, 1991, Garber 2000, Gebo 1992, Hunt et al 1996. Beyond addressing many of the immediate aspects of a primate's dietary, social, and safety requirements, it is possible that wide-ranging physical movement through the structural matrix of tropical canopies is associated with long-term survival of arboreal primates, through a continuance of the capacity to move.…”

“…For example, monkeys comprise a small fraction of the species and biomass in neotropical forests; however, their dispersed defecation of seeds supports diverse populations of animals, and is associated with rain forest regeneration (Andresen 2002, Estrada & Coates-Estrada 1991. Monkeys frequently move in response to local differences in the abundance of resources and the structural aspects of the environment, with disparities in these qualities resulting in variation in the speed, route of travel, and rapid decision-making (Beisner & Isbell 2009, Garber 2000, Hunt et al 1996.…”