Rethinking Merfolk

[Algeh]

If they had a herding culture, they could also scar or tattoo other animals. This could grow out of simple ownership marks (like cattle brands on land), evolve into recording other life events of that animal onto its skin to help them track their animals (this animal was bred with that other one and produced such-and-such calf), and then gradually leap into recording increasingly unrelated information (this animal was bred to that animal and produced a calf in the time when we, the sea people of this area were fighting The War Against Those Other Sea People Who Were Total Jerks) until they were seen as the way to record a lot of not-worth-chiseling-but-still-worth-writing-down information.

Without a reliable way to tan leather, such records would have to be either re-written or lost at the death of the animal, obviously. I could see "book animals" being selectively bred for longer life (and extreme docility in the face of pain) if the use of animals as records really took off. It could also make for an adventure hook to have to find the straying sea cow with the information the PCs needed, which recently escaped the library ranch.

[daremetoidareyo]

If they had a herding culture, they could also scar or tattoo other animals. This could grow out of simple ownership marks (like cattle brands on land), evolve into recording other life events of that animal onto its skin to help them track their animals (this animal was bred with that other one and produced such-and-such calf), and then gradually leap into recording increasingly unrelated information (this animal was bred to that animal and produced a calf in the time when we, the sea people of this area were fighting The War Against Those Other Sea People Who Were Total Jerks) until they were seen as the way to record a lot of not-worth-chiseling-but-still-worth-writing-down information.

Without a reliable way to tan leather, such records would have to be either re-written or lost at the death of the animal, obviously. I could see "book animals" being selectively bred for longer life (and extreme docility in the face of pain) if the use of animals as records really took off. It could also make for an adventure hook to have to find the straying sea cow with the information the PCs needed, which recently escaped the library ranch.

Leatherback Sea turtles or whales would seem to fit the bill quite nicely.