Some of the skulls have a photo with a D size battery. This is to give you an idea of the relative size of the skull

Mountain view skull more info ​here

Cow Elk Skull more info Here

Dreamcatcher 2 more info here

Black and Red antelope skull more info here

Delica Cow Skull more info here

Turquoise Cow skull more info here

rust antelope skull more info ​here

javelina skull more info here