Table 1.

Examples of pressing questions in the field chronobiology.

no.	Question	Case study
1	How variable are rhythms within and between taxa, species, populations and individuals?	1, 2
2	What drives such variation? (e.g. environmental conditions, internal state, sociality, anthropogenic disturbance, global environmental change)	1, 2
3	Are rhythms of captive animals comparable to rhythms of animals in the wild?	1
4	How can we disentangle the relative contribution of endogenous (genes) versus exogenous (environment) drivers of rhythmicity in wild species?
5	Is variation in rhythms associated to fitness?	3