Let us suppose there was another intelligent species living beside man. Let us say it was fully sapient. Could this not be the humble and gregarious dolphin?
Dolphins Reimagined is a short .pdf that is Pathfinder Compatible, and explores their possible sapience. The pdf includes:
Dolphin evolution.
Dolphin biology.
Dolphin behavior.
A full race write up using the rules inthe Advanced... [click here for more]