In memetics, the enlarged human cranium is a type of hollow whose primary "purpose" is accomodating symbiont visitors (memes). As such it resembles the plant swellings known as ant domatia - which are built by the host plants to provide accomodation for ants.
Domatia resemble human skulls, and ants resemble out cultural symbiots - with genetic material composed of memes.
Interestingly, ants of the species Allomerus decemarticulatus create artificial corridors between the domatia of their host plant (Hirtella physophora) to allow them to safely move between them.
What lets ideas move safely from brain to brain? Why: books, telecommunications and the internet! So: here we have the ant equivalent of the internet - based on the crainum-domatia analogy.
The highways are fiercely defended - and the native ants can trap and kill marauding insects that alight upon them.
VideoThe defence of the highways is shown in the following video:
This is an amazing ant domatia story - I plan to see if I can milk it.