Kangaroo (eather eastern or eastern grey, genus Macropus) skull I picked up a while ago (may 25th) and more recently cleaned. As with pretty much anything I find, it's stained with tannin from eucalyptus leaves.
Images 2 and 3: This individual's carcass had been fed on by a fox, as you can see by the tooth marks on the squamosals.
Image 4: The left premolar is also larger than the right one.













