Why do you think emus have their babies in winter?
Australian research has proven that emu breeding season is
dependent upon the length of the day. The amount of daylight
directly influences the production of reproductive hormones.
As the number of daylight hours decrease, amounts of luteinizing
hormone and testosterone in male emus increases, and after about
three and a half months of shortening days, concentration of
prolactin increases. This, in turn, results in a decrease of the
luteinizing and testosterone until the male stops breeding.
Corresponding to these times, the female emu's hormones start to
stimulate egg production and make her more interested in the
male.