Prosimians are a suborder of primates and include lemurs, lorises and tarsiers. Although specialised in many respects, living prosimians generally retain more primitive features than do anthropoids (the other suborder of primates); and in many aspects of teeth, skulls and limbs, they reserve a morphology similar to that found in primates of the Eocene epoch, 50 to 40 million years ago. These primitive features have led many scientists to believe that the study of prosimian behaviour might give us some insights into the behaviour of ancestral primates and primate origins. I am going to explore what has been the major ‘classic’ interpretation of the behaviour of the earliest primates in terms of activity rhythm, locomotion and social behaviour based on the study of modern prosimians and how more recent studies have changed our views on these. Further I am going to explore the major contending views for ecological factors that brought about prosimian origins.
PRIMATE EVOLUTION
Prosimians are a suborder of primates and include lemurs, lorises and tarsiers. Although specialised in many respects, living prosimians generally retain more primitive features than do anthropoids (the other suborder of primates); and in many aspects of teeth, skulls and limbs, they reserve a morphology similar to that found in primates of the Eocene epoch, 50 to 40 million years ago. These primitive features have led many scientists to believe that the study of prosimian behaviour might give us some insights into the behaviour of ancestral primates and primate origins. I am going to explore what has been the major ‘classic’ interpretation of the behaviour of the earliest primates in terms of activity rhythm, locomotion and social behaviour based on the study of modern prosimians and how more recent studies have changed our views on these. Further I am going to explore the major contending views for ecological factors that brought about prosimian origins.
Based on the study of modern prosimians it has been argued that the earliest primates were nocturnal. This view has not been challenged so far despite the fact that there are prosimians that are diurnal or cathemeral. Nevertheless, it seems likely that early primates were nocturnal if one argues that prosimians most closely resemble ancestral behavioural and physical conditions because nearly three quarters of the more primitive prosimians are nocturnal, but there is only one nocturnal monkey. Further, there are contending views on the locomotion of early primates based on the study of modern prosimians. Arboreal quadrupedalism is the most common locomotor behaviour among primates, and most radiations of primates include arboreal quadrupeds. It has been argued that arboreal quadrupedalism characterised both the earliest mammals and the earliest primates because arboreal quadrupeds, in many respects, show a generalised morphology that can easily be modified into any of the more specialised locomotor types. Nevertheless, it has also been argued, for example by Crompton (1995) that especially leaping behaviour in a nocturnal animal was an important selective factor for the evolution of primate stereoscopic vision and thus it has been argued that leaping might have been the ancestral pattern of locomotion. Yet, it seems more likely that in ancestral primate species there were a variety of different locomotion strategies. This can be said with regard to the immense variety of locomotion patterns that exist in modern primates. (Fleagle, 1999)
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- Quote paper
- BA (Oxon), Dip Psych (Open) Christine Langhoff (Author), 2003, Primate Evolution, Munich, GRIN Verlag, https://www.grin.com/document/80251
