Ivory is what all mammalian teeth are made of. The word itself traces its roots back to the ancient Egyptian word for elephant, as that has historically been the primary source of commercial ivory.
This brings to mind all sorts of witticisms when one thinks of the ivory tower (a group of people long in the tooth; dead but ornamental, a place where knowledge is chewed, ground down, etc.).
Looking at scholarship from this perspective can give us something to chew on. We take the wonders of nature, the mystery of human behaviour and dissect them, examining from every angle, and then regurgitating it in an arcane language devoid of life.