The quokka is a social animal and lives in large groups. They eat grass, sedges, succulents and leaves. They can become very sick if fed with things like bread, given to them by visitors to Rottnest Island. Visitors are now told not to feed them. Quokkas breed at any time on the mainland, but in late summer on Rottnest. The female quokka has two babies (called "joeys") in a year. 