Peacocks hibernate through the winter and can be seen in the coldest winter months, although most individuals become active in late March and April. As well as being a harbinger of the coming spring, Peacock butterflies are interesting in many other ways. They are probably the longest-lived butterflies in Britain, with adults surviving from late July, well into the following spring, perhaps into June. Thus, contrary to popular belief that butterflies only live for a few days, some Peacocks may live to see their 11th month (albeit having spent five or six months of their adult lives asleep in hibernation).