Seasonal pelage color change: news based on a South American Rodent

Anais da Academia Brasileira de Ciências

Carolina R. Camargo²  Elton Colares¹  Ana Maria L. Castrucci² 

[1] ,Universidade de São Paulo Instituto de Biociências Departamento de FisiologiaSão Paulo SP ,Brasil

关键词: Color change;    endogenous rhythm;    seasonality;    molt;    pelage color;    Mudança de cor;    ritmo endógeno;    sazonalidade;    muda;    cor da pelagem;   

DOI  :  10.1590/S0001-37652006000100009

来源: SciELO

【 摘 要 】

Mammalian seasonalmolting and color change are known to be influencedby photoperiod changes. Calomys laucha, a South American rodent, exhibits seasonal pelage color change; however, unlike Northern hemisphere rodents, which present a gray or brown color during summer and a whitish color during winter, C. laucha pelage changes from an orange color during summer to a dark gray color during winter. Animals maintained for over a year in stationary photoperiod (LD 12:12h, 22ºC) presented orange pelage color during the summer corresponding month (January), and gray color during the winter corresponding month (July). Same age animals were evaluated during summer or winter months, and also showed different colors. Animals exposed for 12 weeks to summer or winter artificial conditions displayed color change, not according to the environmental conditions, as expected, but similar to that of animals maintained in stationary photoperiod. These results suggest that pelage color change in C. laucha is controlled by an endogenous circannual rhythm. The adaptive function of C. laucha color change is discussed.

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