Profound seasonal shrinking and regrowth of the ossified braincase in phylogenetically distant mammals with similar life histories.

ABSTRACT: Ontogenetic changes in skull shape and size are ubiquitous in altricial vertebrates, but typically unidirectional and minimal in full-grown animals. Red-toothed shrews exhibit a rare exception, where the shape, mass and size of the skull, brain, and several major organs, show significant bidirectional seasonal changes. We now show a similar but male-biased shrinking (16%) and regrowth (8%) in the standardized braincase depth of least weasels (Mustela nivalis). Juvenile weasels also exhibit a growth overshoot, followed by a shrinkage period lasting until the end of their first winter. Only male weasels then regrow during their second summer. High-resolution CT scans suggest areas of the skull are affected differently during shrinking and regrowth in both species. This suggests multiple evol

SUBMITTER: Dechmann DK 

PROVIDER: S-EPMC5304206 | biostudies-literature | 2017 Feb

REPOSITORIES: biostudies-literature