The Nosgar Tribe produces well trained wizards who must be able to keep up with their nomadic lifestyle.
Wizards are presented a staff by their mentor when young. This staff contains cantrips engraved onto the staff. The young wizard memorizes and practices until it is time for his First Strip.
Spells beyond cantrips are engraved, rune by rune, onto strips of dinosaur hide. Only carnivore dinosaurs can be used for these strips, so a First Hunt is part of a wizard's training, but always with friends.
Spell strips wrap around the staff, allowing the wizard to memorize spells keyed specifically to his strips and staff. Strips on another staff would not line up.
Spell strips are roughly six inches per spell level. You can tell the power of a wizard by how many strips are hanging from their staff and their length.
Wizards can learn and copy spells from other sources normally, provided they have strips available. If not, time to hunt!