Only the Yellow-bellied Glider (left) has the teeth strong enough to make these bark incisions, but many other creatures feed on the flowing sap – birds by day and mammals by night.
At one-third the length and one-fifth the weight of a Yellow-bellied Glider, the Sugar Glider (right) has to wait for a feeding opportunity.

Postscript: since posting this image, the Sugar Glider has been shown to consist of three different species. This one is now known as Krefft's Glider (Petaurus notatus), a species that is widespread in eastern Australia.