A comparative study of communication in six taxa of southern African elephant-shrews (macroscelididae)
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Date
1996
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Abstract
Aspects of olfactory, auditory, visual and tactile communication were investigated in five
Elephantulus species (E. brachyrhynchus, E. edwardii, E. intuft, E. myurus, E. rupestris) and
Macroscelides proboscideus, facilitating comparisons among species and genera. The
purpose of this study was to determine whether species specific patterns of communication
could be identified in the southern African elephant-shrews.
Scent gland structure and location was investigated to determine whether species specific
differences existed and to relate gland location to marking behaviour. Prominent scent glands
were found in the oral angel, foot pads, anogenital region and tail of all elephant-shrew
specIes. Marking behaviours such as sandbathing, digging and anal dragging correlated
strongly with sent gland location, but no glandular size and/or structural differences were
apparent among the different elephant-shrew species. Species specific differences in marking
frequencies did exist among the six elephant-shrew taxa, but were unrelated to glandular
development. Choice chamber preference tests indicated that Elephantulus species preferred
conspecific odours, with males showing higher levels of discrimination than females .
Audible vocalizations and footdrumrning were investigated and compared in the sex elephant shrew taxa. Distinct differences were present in the acoustic repertoires of the southern
African elephant-shrew species. Footdrumming showed very clear species specific patterns,
and footdrumming characteristics were compared with an existing morphological phenogram
to derive a possible path of evolution for footdrumming. Visual and tactile communication were investigated by analysis of frequencies and sequences
of behavioural acts. A comparison of male-female interactions of the different taxa showed
differences in behavioural frequencies both between males and females of a species, and
among the different species. Discriminant function analysis showed clear species specific
patterns in the visual! tactile signalling systems of southern African elephant-shrews, and this
was more clearly defined in males.
Elephant-shrews showed higher levels of aggressive behaviour in interspecific encounters,
indicating a possible role of aggression as a premating isolating mechanism between species.
However, no differences in aggressive behaviour between allopatric and sympatric malefemale
interactions could be discerned. Elephant-shrew males showed high frequencies of
submissive behaviour in intraspecific encounters, which may be a strategy to reduce aggression
in conspecific females.
Species specific patterns of behaviour were found to exist in all three modes of communication
investigated, and may all act to some extent as premating isolation mechanisms between
species. However, many of these patterns are very subtle and it is suggested that a
combination of all sensory modalities act together to form each species' signalling system.
Description
Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1996.
Keywords
Elephant shrews., Shrews., Insectivora., Theses--Zoology.