These are real female vervet monkey (Chlorocebus pygerythrus) skulls from South Africa!
These skulls are salvaged from animals that died attacking farm livestock.
These mostly herbivorous primates live in troops of between 10 and 70 individuals.
Interestingly enough, archaeological excavations in the ancient Roman-Egyptian port-town Berenike show they were kept as pets as early as the 1st Century CE and can be found in Mediterranean paintings dating back to 2000BCE!
These ~3.5" skulls are available exclusively in Canada.