Humans in every universe are said to have dæmons, although in some universes they are invisible. In our universe, the books suggest, dæmons are integrated within the person. They have a naturally occurring external physical manifestation in Lyra's universe and some others. Dæmons that are already physical, such as Lyra's dæmon Pantalaimon, remain external even when they visit universes with normally-internal dæmons, such as our own. Typically dæmons and their humans are conscious or sleep at the same time. However, the dæmons of witches and shamans, as revealed in "The Amber Spyglass", can remain awake while their humans sleep, and it is implied in "Northern Lights" that cedarwood can have a soporific effect on dæmons that allows them to sleep even if their humans are awake.