DOI: 10.5061/dryad.g57g1
title: Data from: Growth overshoot and seasonal size changes in the skulls of two weasel species

description: Ontogenetic changes in mammalian skulls are complex. For a very few
 species (i.e. some Sorex shrews), these also include seasonally driven,
 bidirectional size changes within individuals, presumably to reduce energy
 requirements during low resource availabilities. These patterns are poorly
 understood, but are likely most pronounced in high-metabolic species with
 limited means for energy conservation. We used generalized additive models
 to quantify the effect of location, Julian day, age and sex on the length
 and depth of 512 and 847 skulls of stoat (Mustela erminea) and weasel (M.
 nivalis) specimens collected throughout the northern hemisphere. Skull
 length of both species varies between sexes and geographically, with stoat
 skull length positively correlated with latitude. Both species demonstrate
 seasonal and ontogenetic patterns, including a rare, absolute growth
 overshoot in juvenile braincase depth. Standardized braincase depths of
 both species peak in their first summer, then decrease in their first
 winter, followed by a remarkable regrowth that peaks again during their
 second summer. This seasonal pattern varies in magnitude and timing
 between geographical regions and the sexes, matching predictions of
 Dehnel's phenomenon. This suggests implications for the evolution of
 over-wintering strategies in mammals, justifying further research on their
 mechanisms and value, with implications for applied osteology research.
description: Skull metric dataset
 from LaPoint et al. RSOpenScience 2017 Growth overshoot and seasonal size
 changes in the skulls of two weasel speciesThis .csv contains the
 individuals used within our analyses and 18 attributes that were recorded
 or measured by the lead author. These attributes are listed below with
 definitions: species (2 levels: Mustela erminea, Mustela nivalis),
 institution (14 levels: BRUS Muséum d‘Histoire Naturelle Brussels, CUMV
 Cornell University, HELS Finnish Museum of Natural History Helsinki , MFN
 Museum für Naturkunde Berlin, MNHG Muséum d‘Histoire Naturelle Geneva, MRI
 Mammal Research Institute Białowieża , MSU Michigan State University
 Museum, MVZ Museum of Vertebrate Zoology Berkeley, NCMNS North Carolina
 Museum of Natural Sciences Raleigh, NCSU North Carolina State University,
 NYSM New York State Museum Albany, ROM Royal Ontario Museum Toronto, UMMZ
 University of Michigan Museum of Zoology, USNM National Museum of Natural
 History Washington), catalog (unique values, for referencing to actual
 specimens in natural history collections, but not used for analyses), age
 (3 levels: A, adult, J, juvenile, S, subadult, see methods for
 definitions), condylobasal length (numeric, measured in mm), height of
 braincase with auditory bullae (numeric, measured in mm), braincase depth
 (numeric, measured in mm, excludes auditory bullae), braincase width
 (numeric, measured in mm), B2CBL (numeric, relative value of braincase
 depth to condylobasal length), MDY (date, month/day/year), doy (numeric,
 day of year), sex (2 levels: F, female, M, male), country (24 levels,
 Austria, Belarus, Belgium, Canada, China, Czech Republic, Egypt, Finland,
 France, Germany, Italy, Korea, Morocco, Netherlands, Norway, Poland,
 Romania, Russia, Spain, Sweden, Switzerland, Turkey, United Kingdom,
 United States), state (119 levels, state/region/province), location (549
 levels, town/village when provided, otherwise see methods), origin (8
 levels, broad geographic regions that were created to bin specimens into
 spatially similar regions, see Methods for details, all origins were
 included in analyses that present 'global' results), latitude
 (decimal degrees, WGS84), longitude (decimal degrees,
 WGS84).Dataset1_LaPoint_etal_RSOpenScience_RSOS-160947.csv