Function and underlying mechanisms of seasonal colour moulting in mammals and birds: what keeps them changing in a warming world?
Level 5 - mechanism / opinion, no new human data
Level 5 by design analogy; narrative review synthesizing ecological and physiological mechanisms without meta-analysis.
PubMed 29504224 · doi:10.1111/brv.12405
What was done
The authors conducted a comprehensive review synthesizing the adaptive value, ecological functions, and physiological mechanisms (including hair growth, neuroendocrine pathways, and extrinsic factors) of seasonal coat colour (SCC) moulting across more than 20 bird and mammal species in the northern hemisphere (such as snowshoe hare, Arctic fox, and willow ptarmigan) in the context of climate change.
What was found
The abstract reports no quantitative values or effect sizes. Qualitatively, seasonal camouflage against snow was identified as the primary function of SCC moulting across species, with photoperiod acting as the primary driver of moult phenology. Mammals share similarities in hair growth mechanisms and neuroendocrine control, whereas avian mechanisms remain less understood and differ from mammals. The synthesis concluded that phenotypic plasticity in SCC moulting is limited, necessitating evolutionary adaptation to prevent camouflage mismatch.
Why it matters
As climate change reduces snow cover duration, white winter coats against snowless ground create camouflage mismatch that impairs survival. Understanding the limits of moult plasticity and underlying mechanisms helps guide conservation and management strategies for vulnerable arctic and temperate wildlife.
Limits
The abstract provides no quantitative data, meta-analytic statistics, or systematic search parameters. Detailed physiological and genetic mechanisms remain largely unresolved, particularly in avian species compared to mammals.
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