These are real Minute Fruit Bats skulls (Cynopterus minutus)! These megabats are indigenous to the areas of Java, Borneo, Sumatra and Sulawesi.
They are sustainably hunted by the local peoples as a source of food and income. These bats have been studied and rated a level of "Least Concern" on the IUCN index of endangered/at-risk species due to their reproductive rates and widespread distribution.
These specimens measure ~1" long and are available worldwide!