These are real lesser short-nosed fruit bat (Cynopterus brachyotis) skulls! 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 ~1.25" long and are available worldwide!