Impact of Photoperiodicity on Animal Activities |
Day length (Photoperiod) isthe most important and reliable one. It has been involved in regulation ofseasonal cycles of reproduction and associated functions in several animals.Animals respond to the photoperiod (Long and short) to breed at a time in theyear when the survival of the young ones is maximized. Accordingly, animalswith short gestation periods (e.g. Birds) breed during summer, and those withlong gestation period (e.g. Sheep) breed during the winter. These animals arethus called long day and short day breeders, respectively. Photoperiodism alsolinked with migration, hibernation, pelage growth and molt. The two endocrinesecretions i.e. melatonin and thyroid hormone, also play key roles inregulating the seasonal physiology of birds and mammals.