Animal cryptochromes are widely known to regulate circadian clock and can be divided into two types. Type I cryptochromes receive light to initiate the degradation of transcriptional inhibitors, whereas type II cryptochromes directly act as light-irresponsive transcriptional inhibitors. Recent studies reveal that animal cryptochromes also have functions in immune response and carbohydrate metabolism, and are required in light-induced chemical magnetoreception in animals like Drosophila. The further research...