Native mammals include common brushtail possums, common ringtail possums and water rat. Ringtail possums prefer forests of dense brush, particularly eucalyptus forests. Ringtail possums build nests from tree branches and occasionally use tree hollows. The common ringtail possum is nocturnal and well adapted to arboreal life. Common ringtail possum populations severely declined during the 1950s. The koala, common ringtail possum and platypus have been introduced and still survive there. The ringtail possum's molars have sharp and pointed cusps. When foraging, ringtail possums prefer young leaves over old ones. Ringtail possums are territorial and will drive away any strange conspecifics from their nests. As with other marsupials, the common ringtail possum's milk changes through lactation. The park is home to the most easterly distribution of the nocturnal rock ringtail possum. Ringtail possums gain much of their gross energy from reingestion. The oestrous cycle of ringtail possum lasts 28 days. A group of ringtail possums may build several dreys at different sites. Much like the common raccoon, the ringtail is nocturnal and solitary.