Oral tradition can be incredibly rich. Most civilizations in human history had no written language, until very recently. Only a few human cultures created written languages independently (Egyptians, Sudanese, Chinese, Iraqis, and a couple others). Mythology and epics from Ancient Greece, including Homer’s Iliad and Odyssey, were complicated stories passed exclusively by word of mouth from traveling poets. And oral wisdom + verbatim memory were incredibly valued and highly trained skills, so these stories might not have been as distorted across generations as we might assume
We already know orcas spend their entire lives by the sides of the same group, and that the matriarch leader does in fact pass customs, culture, and practices to the next generations by word of mouth. And they likely have greater brainpower for remembrance than us, so who knows, the matriarchs could have books worth of knowledge all in their heads. (And yea parrots and octopus are smart but definitely not on the level of orcas)

I wasn't arguing with anything you said, just adding on stuff I find fascinating, like the possibility that even without that tangible record they perhaps have passed complex information across centuries or even millenniums