Sex ratio at birth in Norway rats: comment on Hornig and McClintock
Article Abstract:
Hornig and McClintock have studied sex ratio variations in Norway rats, and appear to see zygotes as having an equal chance of being male. There may, however, be a variation of the probability of zygotes being male within litters. Hornig and McClintock add back lost pups, and this may not be the most effective way of testing their hypothesis. There is little evidence that sex-related embryonic wastage occurs, and it is more likely that maternal hormone levels affect the chance of zygotes being male.
Publication Name: Animal Behaviour
Subject: Zoology and wildlife conservation
ISSN: 0003-3472
Year: 1997
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Sex allocation in a polygynous mammal with large litters: The wild boar
Article Abstract:
The Trivers & Willard hypothesis of sex-biased maternal investment in polygynous species does not apply to species where mothers produce more than one offspring. Free ranging wild board litters were studied and maternal expenditure per individual offspring was found to be higher for male than female fetuses. Mother quality seem to be linked to litter size, although not to the sex ratio of the litter.
Publication Name: Animal Behaviour
Subject: Zoology and wildlife conservation
ISSN: 0003-3472
Year: 1999
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