Maternal investment and the ontogeny of behaviour in the Atlantic harbour seal

Rosen, David A. S. (1990) Maternal investment and the ontogeny of behaviour in the Atlantic harbour seal. Masters thesis, Memorial University of Newfoundland.

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Abstract

The applicability of differential maternal investment and divergent behavioural ontogeny theories to a marginally dimorphic species, was investigated in the harbour seal. Weight changes of unweaned pups on Miquelon were used to test whether mothers invested more in male than female offspring. Males were found to be heavier at birth than females, but grew at a slower rate prior to weaning. Behavioural observations of mother/pup pairs were used to derive indicators of maternal investment. Nosing behaviour and two indices of nursing and proximity governance appeared to be reasonable predictors of relative investment. In contrast, nursing rejection rates and pup checks were not reasonable measures of investment while the validity of nursing times was inconclusive. The results suggested that, over the course of the nursing period, the pup was increasingly responsible for the level of investment obtained and the maintenance of the pair bond. Unweaned male pups were found to spend less time idle than females during haul outs, and all pups became increasingly more active over the nursing period. Sex difference in behaviour are discussed as an indicator of divergent socio-bioenergetic demands.

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